The branching index measures the effect of long-chain branches on the size of a macromolecule in solution. It is defined as g = b2>/l2>, where sb is the mean square radius of gyration of the branched macromolecule in a given solvent, and sl is the mean square radius of gyration of an otherwise identical linear macromolecule in the same solvent at the same temperature. A value greater than 1 indicates an increased radius of gyration due to branching.
|
|
In polymer chemistry, degenerative chain transfer (also called degenerate chain transfer) is a process that can occur in a radical polymerization whereby reactivity of active centres are changed, hence significantly influencing the molecular weight distribution of the resulting product. In chain polymerization processes it is observed that during the chemical reactions an active centre on a growing chain is transferred from a growing macromolecule - P• - or oligomer to another molecule (transfer agent XR) or to another site on the same molecule. :P• + XR → PX + R• This transfer involves termination of the initially growing chain to the completed macromolecule PX, where X denotes one end-group of the macromolecule. The example shows that the growing macromolecule as well as the transfer agent are consumed during this process.
|
|
However, recent experiments and theoretical models found that depletion forces can be enthalpically driven. In these instances, the intricate balance of interactions between the solution components results in the net exclusion of cosolute from macromolecule. This exclusion results in an effective stabilization of the macromolecule self-association, which can be not only enthalpically dominated, but also entropically unfavorable.
|
|
If a reaction does occur, it becomes clear that the bacteria does possess an exoenzyme, and which macromolecule is hydrolyzed determines its identity.
|
|
218, 365–393(1981). who employed modern high-pressure columns and equipment. It has since found many applications, particularly in the realm of biological macromolecule purification.
|
|
In chemistry, sedimentation has been used to measure the size of large molecules (macromolecule), where the force of gravity is augmented with centrifugal force in an ultracentrifuge.
|
|
Stokes radius is sometimes used synonymously with effective hydrated radius in solution. Hydrodynamic radius, RH, can refer to the Stokes radius of a polymer or other macromolecule.
|
|
Glucose binds to hexokinase in the active site at the beginning of glycolysis. In biochemistry and molecular biology, a binding site is a region on a macromolecule such as a protein that binds to another molecule with specificity. The binding partner of the macromolecule is often referred to as a ligand. Ligands may include other proteins (resulting in a protein-protein interaction), enzyme substrates, second messengers, hormones, or allosteric modulators.
|
|
Complicated biomacromolecules, on the other hand, require multi-faceted structural description such as the hierarchy of structures used to describe proteins. In British English, the word "macromolecule" tends to be called "high polymer".
|
|
The apparent hydrodynamic size can then be used to approximate molecular mass using a series of macromolecule- specific standards. As this requires calibration, it's frequently described as a "relative" molecular mass determination method.
|
|
However, some people (such as fellow researcher and colleague Esther Lederberg) thought that Crick was unduly optimistic It was clear that some macromolecule such as a protein was likely to be the genetic molecule.Crick (1990) p. 32 However, it was well known that proteins are structural and functional macromolecules, some of which carry out enzymatic reactions of cells. In the 1940s, some evidence had been found pointing to another macromolecule, DNA, the other major component of chromosomes, as a candidate genetic molecule.
|
|
Chemical structure of a polypeptide macromolecule A macromolecule is a very large molecule, such as protein, commonly composed of the polymerization of smaller subunits called monomers. They are typically composed of thousands of atoms or more. A substance that is composed of monomers is called a polymer. The most common macromolecules in biochemistry are biopolymers (nucleic acids, proteins, and carbohydrates) and large non-polymeric molecules (such as lipids and macrocycles), synthetic fibers as well as experimental materials such as carbon nanotubes.
|
|
The only significant difference between chlorocruorin and erythrocruorin is that chlorocruorin carries an abnormal heme group structure. This enormous macromolecule is typically found free floating in the plasma, and not contained within red blood cells.
|
|
Conformational changes can elicit the motion of a protein complex. Kinesin walking on a microtubule is a molecular biological machine using protein domain dynamics on nanoscales In biochemistry, a conformational change is a change in the shape of a macromolecule, often induced by environmental factors. A macromolecule is usually flexible and dynamic. It can change its shape in response to changes in its environment or other factors; each possible shape is called a conformation, and a transition between them is called a conformational change.
|
|
The Hill–Langmuir equation was originally formulated by Archibald Hill in 1910 to describe the sigmoidal O2 binding curve of haemoglobin. The binding of a ligand to a macromolecule is often enhanced if there are already other ligands present on the same macromolecule (this is known as cooperative binding). The Hill–Langmuir equation is useful for determining the degree of cooperativity of the ligand(s) binding to the enzyme or receptor. The Hill coefficient provides a way to quantify the degree of interaction between ligand binding sites.
|
|
The mesangium is exposed to macromolecules from the capillary lumen as they are separated only by fenestrated endothelium without basement membrane. Mesangial cells play a role in restricting macromolecules from accumulating in the mesangial space by receptor- independent uptake processes of phagocytosis, micro- and macro-pinocytosis, or receptor-dependent processes and then transported along the mesangial stalk. Size, charge, concentration, and affinity for mesangial cell receptors of the macromolecule affects how the macromolecule is removed. Triglycerides may undergo pinocytosis and antibody IgG complexes may lead to activation of adhesion molecules and chemokines by mesangial cells.
|
|
Immunoassays rely on the ability of an antibody to recognize and bind a specific macromolecule in what might be a complex mixture of macromolecules. In immunology the particular macromolecule bound by an antibody is referred to as an antigen and the area on an antigen to which the antibody binds is called an epitope. In some cases, an immunoassay may use an antigen to detect for the presence of antibodies, which recognize that antigen, in a solution. In other words, in some immunoassays, the analyte may be an antibody rather than an antigen.
|
|
Precise knowledge of tacticity of a polymer also helps understanding at what temperature a polymer melts, how soluble it is in a solvent and its mechanical properties. A tactic macromolecule in the IUPAC definition is a macromolecule in which essentially all the configurational (repeating) units are identical. Tacticity is particularly significant in vinyl polymers of the type -H2C-CH(R)- where each repeating unit with a substituent R on one side of the polymer backbone is followed by the next repeating unit with the substituent on the same side as the previous one, the other side as the previous one or positioned randomly with respect to the previous one. In a hydrocarbon macromolecule with all carbon atoms making up the backbone in a tetrahedral molecular geometry, the zigzag backbone is in the paper plane with the substituents either sticking out of the paper or retreating into the paper.
|
|
Hemichromes form an insoluble macromolecule (macromolecular aggregate) by copolymerization with the cytoplasm of band 3. Covalent bonds reinforce the aggregate interactions of the hemichromes which are accumulated on the surface of the membrane. However, hemichromes are less stable than their native form.
|
|
Structural elements in lignins are the building blocks in the macromolecule corresponding to the monomers and the intra-molecular bonds. For lignins, the structural elements are often determined by pyrolysis-gas chromatography-mass spectrometry (py-GC-MS or nuclear magnetic resonance spectroscopy (NMR).
|
|
Sequence-defined polymer (Syn. sequence-specific polymer, sequence-ordered polymer) is a uniform macromolecule with an exact chain-length and a perfectly defined sequence of monomers. In other words, each monomer unit is at a defined position in the chain e.g. peptides, proteins, oligonucleotides.
|
|
Polymers of lipid II form a linear glycan chain. This reaction is catalyzed by the glycosyltransferases of family 51 (GT51). Transpeptidases cross link the chains and form a net-like peptidoglycan macromolecule. The resulting glycopeptide is an essential part of the envelope of many bacteria.
|
|
There is a predicted N-terminal longin domain within the Nprl3 protein (amino acids 4-168). At the C terminus there are three consecutive winged helix turn helix (HTH) domains. These regions are predicted bind to another macromolecule, which could be DNA, RNA or protein.
|
|
In syndiotactic or syntactic macromolecules the substituents have alternate positions along the chain. The macromolecule consists 100% of racemo diads. Syndiotactic polystyrene, made by metallocene catalysis polymerization, is crystalline with a melting point of 161 °C. Gutta percha is also an example for Syndiotactic polymer.
|
|
In enzymology, a N-acetylgalactosamine-6-sulfatase () is an enzyme that catalyzes the chemical reaction of cleaving off the 6-sulfate groups of the N-acetyl-D-galactosamine 6-sulfate units of the macromolecule chondroitin sulfate and, similarly, of the D-galactose 6-sulfate units of the macromolecule keratan sulfate. This enzyme belongs to the family of hydrolases, specifically those acting on sulfuric ester bonds. The systematic name of this enzyme class is N-acetyl-D-galactosamine-6-sulfate 6-sulfohydrolase. Other names in common use include chondroitin sulfatase, chondroitinase, galactose-6-sulfate sulfatase, acetylgalactosamine 6-sulfatase, N-acetylgalactosamine-6-sulfate sulfatase, and N-acetylgalactosamine 6-sulfatase.
|
|
As the Hill coefficient is increased, the saturation curve becomes steeper. In biochemistry and pharmacology, the Hill equation refers to two closely related equations that reflect the binding of ligands to macromolecules, as a function of the ligand concentration. A ligand is "a substance that forms a complex with a biomolecule to serve a biological purpose" (ligand definition), and a macromolecule is a very large molecule, such as a protein, with a complex structure of components (macromolecule definition). Protein-ligand binding is an example of this kind of binding, which typically changes the structure of the target protein, thereby changing its function in a cell.
|
|
Isotactic polymers are composed of isotactic macromolecules (IUPAC definition).IUPAC macromolecular glossary In isotactic macromolecules all the substituents are located on the same side of the macromolecular backbone. An isotactic macromolecule consists of 100% meso diads. Polypropylene formed by Ziegler–Natta catalysis is an isotactic polymer.
|
|
Robertson- Anderson joined the faculty of University of San Diego in 2009. She leads the Robertson-Anderson biophysics laboratory. She uses single-molecule microscopy and optical tweezers to understand macromolecule dynamics in soft matter. Using optical tweezer microrheology, Robertson-Anderson can measure intermolecular forces with piconewton precision.
|
|
The name “Dendronized Polymer” which meanwhile is internationally accepted was coined by Schlüter in 1998.A. D. Schlüter, Top. Curr. Chem. 1998, 197, 165. The first report on such a macromolecule which at that time was called “Rod-shaped Dendrimer” goes back to a patent by Tomalia in 1987D.
|
|
In biomedicine and biotechnology, sensors which detect analytes thanks to a biological component, such as cells, protein, nucleic acid or biomimetic polymers, are called biosensors. Whereas a non-biological sensor, even organic (carbon chemistry), for biological analytes is referred to as sensor or nanosensor. This terminology applies for both in-vitro and in vivo applications. The encapsulation of the biological component in biosensors, presents a slightly different problem that ordinary sensors; this can either be done by means of a semipermeable barrier, such as a dialysis membrane or a hydrogel, or a 3D polymer matrix, which either physically constrains the sensing macromolecule or chemically constrains the macromolecule by bounding it to the scaffold.
|
|
This enormous macromolecule is free floating in the plasma, and not contained within red blood cells. The ratio of plasma hemoglobin to chlorocruorin is high in younger individuals, but this ratio reverses as the animal matures. Presumably this reflects a lower oxygen consumption in the adult worm, relative to the juveniles.
|
|
The function of polyamine is very diverse in that it performs a key macromolecule to cellular membrane. Because of their essential roles in plant, mutation of polyamines can cause critical damage on plants.Rakesh Minocha, Rajtilak Majumdar, Subhash C. Minocha, Polyamines and abiotic stress in plants: a complex relationship. Front Plant Sci.
|
|
The emergence of such an incredibly complex structure, a macromolecule that converts the energy of sunlight into potentially useful work with efficiencies that are impossible in ordinary experience, seems almost magical at first glance. Thus, it is of considerable interest that, in essence, the same structure is found in purple bacteria.
|
|
In fluorescence spectroscopy, the fluorescence anisotropy, calculated from the polarization properties of fluorescence from samples excited with plane-polarized light, is used, e.g., to determine the shape of a macromolecule. Anisotropy measurements reveal the average angular displacement of the fluorophore that occurs between absorption and subsequent emission of a photon.
|
|
A sequence in biology is the one-dimensional ordering of monomers, covalently linked within a biopolymer; it is also referred to as the primary structure of a biological macromolecule. While it can refer to many different molecules, the term sequence is most often used to refer to a DNA sequence.
|
|
CyaA binds to calcium ions selectively and non-covalently, along with other proteins and protein complexes. It has also been shown to interact with one or more specific sites on a receptor molecule, a macromolecule that combines with a hormone, neurotransmitter, drug, or intracellular messenger to initiate a change in cell function.
|
|
DNA stores the information required to assemble, maintain and reproduce every living organism. A protein is a large molecule ("macromolecule") made up of smaller subunits, amino acids. DNA sequences are made up of codons, three-long nucleotide stretches, that correspond to specific amino acids. DNA creates RNA which then helps synthesize proteins.
|
|
The macromonomer route results in shorter chains for higher generations and the attach-to route is prone to lead to structure imperfections as an enormous number of chemical reactions have to be performed for each macromolecule. Figure 4. The two main synthetic approaches: The macromonomer route (left) and the attach-to route (right).
|
|
Nestin is an intermediate filament (IF) protein that assists with IF polymerization and macromolecule stability. Intermediate filaments are an integral part of cell motility, a requirement for any large migration or cellular reaction. Nestin is normally present during (CNS) development and reactivates after minor stresses to the nervous system. However, Frisen et al.
|
|
Different rows of DNA will move at different speeds because some DNA pieces are larger than others. Thus if two DNA samples show a similar pattern on the gel electrophoresis, one can tell that these DNA samples match. Macromolecule blotting is a process performed after gel electrophoresis. An alkaline solution is prepared in a container.
|
|
Polymer Journal is the official journal of the Society of Polymer Science, Japan (SPSJ) and publishes original articles, notes, short communications and reviews on developments in macromolecule research. It is an international peer-reviewed journal that is published on a monthly basis. The current Editor-in-Chief is Keiji Tanaka of Kyushu University, Japan.
|
|
A mimotope is a macromolecule, often a peptide, which mimics the structure of an epitope. Because of this property it causes an antibody response similar to the one elicited by the epitope. An antibody for a given epitope antigen will recognize a mimotope which mimics that epitope. Mimotopes are commonly obtained from phage display libraries through biopanning.
|
|
Hermann had recently published results on cellulose models and Voita was working on algae cell membranes. From that point on, they began collaborating on macromolecules. Staudinger studied macromolecules and their chemical structure and collaborated with Hermann for many years. In the 1940s she returned to applying macromolecule studies to biology, conducting trials from 1945 forward on living cells.
|
|
Additional steps can be taken to further refine each of the obtained pellets. Sedimentation depends on mass, shape, and partial specific volume of a macromolecule, as well as solvent density, rotor size and rate of rotation. The sedimentation velocity can be monitored during the experiment to calculate molecular weight. Values of sedimentation coefficient (S) can be calculated.
|
|
Glycosylation is the process by which a carbohydrate is covalently attached to a target macromolecule, typically proteins and lipids. This modification serves various functions. For instance, some proteins do not fold correctly unless they are glycosylated. In other cases, proteins are not stable unless they contain oligosaccharides linked at the amide nitrogen of certain asparagine residues.
|
|
Depletion forces were first described by Sho Asakura and Fumio Oosawa in 1954. In their model, the force is always considered to be attractive. Additionally, the force is considered to be proportional to the osmotic pressure. The Asakura–Oosawa model assumes low macromolecule densities and that the density distribution, \rho(r), of the macromolecules is constant.
|
|
Since the chelated platinum ion is tightly bound to the chelating agent in the form of macromolecule, therefore, toxicity problem would not be an issue. Silver, platinum and gold are best known precious metals. However, from a more comprehensive and chemistry point of view, they should be described as inert metals. Inert metals are very stable.
|
|
The degree of polymerization, or DP, is the number of monomeric units in a macromolecule or polymer or oligomer molecule.IUPAC Definition in Compendium of Chemical Terminology (IUPAC Gold Book)Cowie J.M.G. Polymers: Chemistry and Physics of Modern Materials (2nd ed. Blackie 1991), p.10 Allcock H.R., Lampe F.W. and Mark J.P. Contemporary Polymer Chemistry (3rd ed.
|
|
The depression of metabolic rate during aestivation causes a reduction in macromolecule synthesis and degradation. To stabilize the macromolecules, aestivators will enhance antioxidant defenses and elevate chaperone proteins. This is a widely used strategy across all forms of hypometabolism. These physiological and biochemical concerns appear to be the core elements of hypometabolism throughout the animal kingdom.
|
|
Hamamouch, Noureddine. "Engineering Resistance to Orobanche Aegyptiaca: Evidence of Sarcotoxin IA as an Anti-Parasite Protein and Macromolecule Movement from Host to Parasite." Diss. Virginia Polytechnic Institute and State University, 2004 Most forms of biological control are still being developed and studied, although three species are potential forms of control: Fusarium oxysporum, F. solani, and Sclerotinia sclerotiorum.
|
|
LigandScout is computer software that allows creating three-dimensional (3D) pharmacophore models from structural data of macromolecule–ligand complexes, or from training and test sets of organic molecules. It incorporates a complete definition of 3D chemical features (such as hydrogen bond donors, acceptors, lipophilic areas, positively and negatively ionizable chemical groups) that describe the interaction of a bound small organic molecule (ligand) and the surrounding binding site of the macromolecule. These pharmacophores can be overlaid and superimposed using a pattern-matching based alignment algorithm that is solely based on pharmacophoric feature points instead of chemical structure. From such an overlay, shared features can be interpolated to create a so-called shared-feature pharmacophore that shares all common interactions of several binding sites/ligands or extended to create a so-called merged-feature pharmacophore.
|
|
Compounds that make up organisms may be divided into macromolecules and other, smaller molecules. The four groups of macromolecule are nucleic acids, proteins, carbohydrates and lipids. Nucleic acids (specifically deoxyribonucleic acid, or DNA) store genetic data as a sequence of nucleotides. The particular sequence of the four different types of nucleotides (adenine, cytosine, guanine, and thymine) dictate many characteristics that constitute the organism.
|
|
The blob model, explaining the entanglement of long polymer chains. The tube model, explaining the basically one-dimensional mobility of long polymer chains. Entangled polymers are characterized with effective internal scale, commonly known as the length of macromolecule between adjacent entanglements M_{e}. Entanglements with other polymer chains restrict polymer chain motion to a thin virtual tube passing through the restrictions.
|
|
The index is measured by determining the fraction of the polymer insoluble in boiling heptane. Commercially available polypropylenes usually have an isotactic index between 85 and 95%. The tacticity effects the polymers physical properties. As the methyl group is in isotactic propylene consistently located at the same side, it forces the macromolecule in a helical shape, as also found in starch.
|
|
Abstract Different crosslinking methods can be implemented for the design of a hydrogel. By definition, a crosslinked polymer gel is a macromolecule that solvent will not dissolve. Due to the polymeric domains created by crosslinking in the gel microstructure, hydrogels are not homogenous within the selected solvent system. The following sections summarize the chemical and physical methods by which hydrogels are crosslinked.
|
|
RasMol is a computer program written for molecular graphics visualization intended and used mainly to depict and explore biological macromolecule structures, such as those found in the Protein Data Bank. It was originally developed by Roger Sayle in the early 1990s.Roger Sayle and E. James Milner- White. "RasMol: Biomolecular graphics for all", Trends in Biochemical Sciences (TIBS), September 1995, Vol.
|
|
Structure of a polyphenylene dendrimer macromolecule reported by Müllen, et al.Some examples of macromolecules are synthetic polymers (plastics, synthetic fibers, and synthetic rubber), graphene, and carbon nanotubes. Polymers may be prepared from inorganic matter as well as for instance in inorganic polymers and geopolymers. The incorporation of inorganic elements enables the tunability of properties and/or responsive behavior as for instance in smart inorganic polymers.
|
|
More generally they are covalently bonded to a macromolecule, serving as a marker (or dye, or tag, or reporter) for affine or bioactive reagents (antibodies, peptides, nucleic acids). Fluorophores are notably used to stain tissues, cells, or materials in a variety of analytical methods, i.e., fluorescent imaging and spectroscopy. Fluorescein, via its amine-reactive isothiocyanate derivative fluorescein isothiocyanate (FITC), has been one of the most popular fluorophores.
|
|
Enzyme catalysis of chemical reactions occur with high selectivity and rate. The substrate is activated in a small part of the enzyme's macromolecule called the active site. There, the binding of a substrate close to functional groups in the enzyme causes catalysis by so- called proximity effects. It is possible to create similar catalysts from small molecule by combining substrate-binding with catalytic functional groups.
|
|
The principal cytoplasmic proteins are myosin and actin (also known as "thick" and "thin" filaments, respectively) which are arranged in a repeating unit called a sarcomere. The interaction of myosin and actin is responsible for muscle contraction. Every single organelle and macromolecule of a muscle fiber is arranged to ensure form meets function. The cell membrane is called the sarcolemma with the cytoplasm known as the sarcoplasm.
|
|
An example of this assertion in drug design is the substrate specificity for the binding of IDD 594 to human aldose reductase. E.I. Howard reported the best resolution for this monomeric enzyme. This biological macromolecule consists of 316 residues, and it reduces aldoses, corticosteroids, and aldehydes. D-sorbitol, a product of the enzymatic conversion of D-glucose, is thought to contribute to the downstream effects of the pathology of diabetes.
|
|
It is believed that the macromolecule accountable for maintaining the dormant state has a protein coat rich in cystine, stabilized by S-S linkages. A reduction in these linkages has the potential to change the tertiary structure, causing the protein to unfold. This conformational change in the protein is thought to be responsible for exposing active enzymatic sites necessary for endospore germination. Endospores can stay dormant for a very long time.
|
|
ATR-FTIR is also used as a tool in pharmacological research to investigate protein/pharmaceutical interactions in detail. Water-soluble proteins to be investigated require Polyhistidine-tags, allowing the macromolecule to be anchored to a lipid bilayer, which is attached to a Germanium crystal or other suitable optical media. Internal reflection with and without applied pharmaceutical or ligand will produce difference spectra to study conformational changes of the proteins upon binding.
|
|
The production of a particular digestive exoenzyme by a bacterial cell can be assessed using plate assays. Bacteria are streaked across the agar, and are left to incubate. The release of the enzyme into the surroundings of the cell cause the breakdown of the macromolecule on the plate. If a reaction does not occur, this means that the bacteria does not create an exoenzyme capable of interacting with the surroundings.
|
|
The essential of crystal formation is letting the sample solution to reach the supersaturated state. Supersaturation is defined by McPherson et al. 2014 as “a non-equilibrium condition in which some quantity of the macromolecule in excess of the solubility limit, under specific chemical and physical conditions, is nonetheless present in solution.” The formation of solids in solution, such as aggregation and crystals, favors the re-establishment of equilibrium.
|
|
SBS block copolymer schematic microstructure Block copolymers comprise two or more homopolymer subunits linked by covalent bonds. The union of the homopolymer subunits may require an intermediate non-repeating subunit, known as a junction block. Diblock copolymers have two distinct blocks; triblock copolymers have three. Technically, a block is a portion of a macromolecule, comprising many units, that has at least one feature which is not present in the adjacent portions.
|
|
Real linear polymer chains as recorded using an atomic force microscope A polymer is a macromolecule, composed of many similar or identical repeated subunits. Polymers are common in, but not limited to, organic media. They range from familiar synthetic plastics to natural biopolymers such as DNA and proteins. Their unique elongated molecular structure produces unique physical properties, including toughness, viscoelasticity, and a tendency to form glasses and semicrystalline structures.
|
|
Structure of double-stranded DNA, the product of DNA synthesis, showing individual nucleotide units and bonds. DNA synthesis is the natural or artificial creation of deoxyribonucleic acid (DNA) molecules. DNA is a macromolecule made up of nucleotide units, which are linked by covalent bonds and hydrogen bonds, in a repeating structure. DNA synthesis occurs when these nucelotide units are joined together to form DNA; this can occur artificially (in vitro) or naturally (in vivo).
|
|
Schematic setup of different types of FPM. As a fundamental physical dimension of fluorescence, polarization has been applied extensively in biological researches. Through fluorescence polarization microscopy (FPM), the dipole orientation as well as the intensity of fluorescent probes could be measured. Compared with X-ray crystallography or electron microscopy which could elucidate ultra-high resolution of individual proteins or macromolecule assemblies, FPM don't require complex sample preparation which made it suitable for live cell imaging.
|
|
The functionality of a monomeric structural unit is defined as the number of covalent bonds which it forms with other reactants.Definition of functionality in IUPAC Gold Book A structural unit in a linear polymer chain segment forms two bonds and is therefore bifunctional, as for the PET structural units above. Other values of functionality exist. Unless the macromolecule is cyclic, it will have monovalent structural units at each end of the polymer chain.
|
|
Carbon monoxide releasing materials (CORMAs) are essentially novel drug formulations and drug delivery platforms which have emerged to overcome the pharmaceutical limitations of most CORM species. An exemplary CORMA developed by Hubbell consists of a formulation of micelles prepared from triblock copolymers with a CORM entity, which is triggered for release via addition of cysteine. Other CO-releasing scaffolds include polymers, peptides, silica nanoparticles, nanodiamond, magnetic nanoparticles, nanofiber gel, metallodendrimers, and CORM-protein (macromolecule) conjugates.
|
|
In its coil state, the radius of gyration of the macromolecule scales as its chain length to the three-fifths power. As it passes through the coil–globule transition, it shifts to scaling as chain length to the half power (at the transition) and finally to the one third power in the collapsed state. The direction of the transition is often specified by the constructions 'coil-to- globule' or 'globule-to-coil' transition.
|
|
In structural biology, ambiguity has been recognized as a problem for studying protein conformations. The analysis of a protein three-dimensional structure consists in dividing the macromolecule into subunits called domains. The difficulty of this task arises from the fact that different definitions of what a domain is can be used (e.g. folding autonomy, function, thermodynamic stability, or domain motions), which sometimes results in a single protein having different—yet equally valid—domain assignments.
|
|
The molecular zipper is a toy model which may be used to illustrate the Lee–Yang theory. It has the advantage that all quantities, including the zeros, can be computed analytically. The model is based on a double-stranded macromolecule with N links that can be either open or closed. For a fully closed zipper, the energy is zero, while for each open link the energy is increased by an amount \varepsilon.
|
|
This is a rate-limiting step. It decreases the glycolysis activity and allows carbohydrate metabolites to enter other pathways, like hexosamine pathway, Uridine diphosphate glucose–glucose synthesis, glycerol synthesis and Pentose phosphate pathway or PPP. It helps in generating macromolecule precursors, that are necessary to support cell proliferation, and reducing equivalents such as NADPH. It has been observed in some studies that MYC promotes expression of PKM2 over PKM1 by modulating exon splicing.
|
|
The family within each college of each molecule across the four years who belong to a given advisor is referred to as a macromolecule. Every year, the Colleges compete in the “College Olympics” in late October, a competition that includes athletic events and sports as well as art battles and dance-offs. Sabin College is the defending Olympics champion from both 2017 and 2018. Taussig College has held the Spirit Award each consecutive Olympics since 2016.
|
|
Immunoperoxidase is a type of immunostain used in molecular biology, medical research, and clinical diagnostics. In particular, immunoperoxidase reactions refer to a sub-class of immunohistochemical or immunocytochemical procedures in which the antibodies are visualized via a peroxidase-catalyzed reaction. Immunohistochemistry and immunocytochemistry are methods used to determine in which cells or parts of cells a particular protein or other macromolecule are located. These stains use antibodies to bind to specific antigens, usually of protein or glycoprotein origin.
|
|
ELS is useful for characterizing information about the surface of proteins. Ware and Flygare (1971) demonstrated that electrophoretic techniques can be combined with laser beat spectroscopy in order to simultaneously determine the electrophoretic mobility and diffusion coefficient of bovine serum albumin. The width of a Doppler shifted spectrum of light that is scattered from a solution of macromolecules is proportional to the diffusion coefficient. The Doppler shift is proportional to the electrophoretic mobility of a macromolecule.
|
|
Anisotrpic Network Model use an elastic mass-and-spring network to represent biological macromolecule (Elastic Network Model) The Anisotropic Network Model (ANM) is a simple yet powerful tool made for Normal Mode Analysis of proteins, which has been successfully applied for exploring the relation between function and dynamics for many proteins. It is essentially an Elastic Network Model for the Cα atoms with a step function for the dependence of the force constants on the inter-particle distance.
|
|
Reptation—motion of long linear, entangled macromolecules amorphous polymers. Reptation is the thermal motion of very long linear, entangled macromolecules in polymer melts or concentrated polymer solutions. Derived from the word reptile, reptation suggests the movement of entangled polymer chains as being analogous to snakes slithering through one another. Pierre-Gilles de Gennes introduced (and named) the concept of reptation into polymer physics in 1971 to explain the dependence of the mobility of a macromolecule on its length.
|
|
For many chemical and biological applications, it is useful to quantify the concentration of upconversion nanoparticles in terms of molecular mass. For this purpose, each nanoparticle can be considered a macromolecule. To calculate the molecular mass of a nanoparticle, the size of the nanoparticle, the size and shape of the unit cell structure, and the unit cell elemental composition must be known. These parameters can be obtained from transmission electron microscopy and X-ray diffraction respectively.
|
|
An example of a pharmacophore model. A pharmacophore is an abstract description of molecular features that are necessary for molecular recognition of a ligand by a biological macromolecule. IUPAC defines a pharmacophore to be "an ensemble of steric and electronic features that is necessary to ensure the optimal supramolecular interactions with a specific biological target and to trigger (or block) its biological response". A pharmacophore model explains how structurally diverse ligands can bind to a common receptor site.
|
|
By definition, a crosslinked polymer gel is a macromolecule that cannot dissolve. Due to the polymeric domains created by crosslinking, in the gel microstructure, hydrogels are not homogenous within the solvent system in which they are placed into. Swelling of the network, however, does occur in the presence of a proper solvent. Voids in the microstructure of the gel where crosslinking agent or monomer has aggregated during polymerization can cause solvent to diffuse into or out of the hydrogel.
|
|
With biomacromolecules CD is particularly useful for determining the secondary structure. By way of contrast, in LD experiments the molecules need to have a preferential orientation otherwise the LD=0. With biomacromolecules flow orientation is often used, other methods include stretched films, magnetic fields, and squeezed gels. Thus LD gives information such as alignment on a surface or the binding of a small molecule to a flow-oriented macromolecule, endowing it with different functionality from other spectroscopic techniques.
|
|
Amber is heterogeneous in composition, but consists of several resinous bodies more or less soluble in alcohol, ether and chloroform, associated with an insoluble bituminous substance. Amber is a macromolecule by free radical polymerization of several precursors in the labdane family, e.g. communic acid, cummunol, and biformene.Manuel Villanueva-García, Antonio Martínez-Richa, and Juvencio Robles Assignment of vibrational spectra of labdatriene derivatives and ambers: A combined experimental and density functional theoretical study Arkivoc (EJ-1567C) pp.
|
|
Equipment for analytical continuous-elution gel electrophoresis: electrophoresis chamber, peristaltic pump, fraction collector, buffer recirculation pump and UV detector (in a refrigerator), power supply and recorder (on a table). Cf. QPNC-PAGE.Electroelution is a method used to extract a nucleic acid or a protein sample from an electrophoresis gel by applying a negative current in the plane of the smallest dimension of the gel, drawing the macromolecule to the surface for extraction and subsequent analysis. Electroblotting is based upon the same principle.
|
|
309x309px A sequence-controlled polymer is a macromolecule, in which the sequence of monomers is controlled to some degree. This control can be absolute but not necessarily. In other words, a sequence-controlled polymer can be uniform (its dispersity Ð is equal to 1) or non-uniform (Ð>1). For example, an alternating copolymer synthesized by radical polymerization is a sequence-controlled polymer, even if it is also a non-uniform polymer, in which chains have different chain-lengths and slightly different compositions.
|
|
Reptation is the thermal motion of very long linear, entangled macromolecules in polymer melts or concentrated polymer solutions. Derived from the word reptile, reptation suggests the movement of entangled polymer chains as being analogous to snakes slithering through one another. Pierre-Gilles de Gennes introduced (and named) the concept of reptation into polymer physics in 1971 to explain the dependence of the mobility of a macromolecule on its length. Reptation is used as a mechanism to explain viscous flow in an amorphous polymer.
|
|
Aerogel structure results from a sol-gel polymerization, which is when monomers (simple molecules) react with other monomers to form a sol or a substance that consists of bonded, cross-linked macromolecules with deposits of liquid solution among them. When the material is critically heated, the liquid evaporates and the bonded, cross-linked macromolecule frame is left behind. The result of the polymerization and critical heating is the creation of a material that has a porous strong structure classified as aerogel.Aerogel Structure . Str.llnl.gov.
|
|
The tertiary structure of a protein or any other macromolecule is its three-dimensional structure, as defined by the atomic coordinates. Proteins and nucleic acids fold into complex three-dimensional structures which result in the molecules' functions. While such structures are diverse and complex, they are often composed of recurring, recognizable tertiary structure motifs and domains that serve as molecular building blocks. Tertiary structure is considered to be largely determined by the biomolecule's primary structure (its sequence of amino acids or nucleotides).
|
|
The starter unit for the biosynthesis of streptogramin A is isobutyryl-CoA, which is given by the amino acid valine after it has undergone transamination and branched-chain keto acid dehydrogenation. Two rounds of chain extension with malonate follow. An NRPS module introduces a glycine residue into the growing polyketide chain, followed by two more rounds of chain extension with malonate. At this point, four enzymes use acetyl-CoA to add a methyl group to position 12 on the macromolecule.
|
|
For polar solvents, valinomycin will mainly expose the carbonyls to the solvent and in nonpolar solvents the isopropyl groups are located predominantly on the exterior of the molecule. This conformation changes when valinomycin is bound to a potassium ion. The molecule is "locked" into a conformation with the isopropyl groups on the exterior. It is not actually locked into configuration because the size of the molecule makes it highly flexible, but the potassium ion gives some degree of coordination to the macromolecule.
|
|
X-ray crystallography is the primary method for determining the molecular conformations of biological macromolecules, particularly protein and nucleic acids such as DNA and RNA. In fact, the double-helical structure of DNA was deduced from crystallographic data. The first crystal structure of a macromolecule was solved in 1958, a three-dimensional model of the myoglobin molecule obtained by X-ray analysis. The Protein Data Bank (PDB) is a freely accessible repository for the structures of proteins and other biological macromolecules.
|
|
This type of reaction can continue to build larger and larger silicon-containing molecules by the process of polymerization. Thus, a polymer is a huge molecule (or macromolecule) formed from hundreds or thousands of units called monomers. The number of bonds that a monomer can form is called its functionality. Polymerization of silicon alkoxide, for instance, can lead to complex branching of the polymer, because a fully hydrolyzed monomer Si(OH)4 is tetrafunctional (can branch or bond in 4 different directions).
|
|
Dendronized polymers can contain several thousands of dendrons in one macromolecule and have a stretched out, anisotropic structure. In this regard they differ from the more or less spherically shaped dendrimers, where a few dendrons are attached to a small, dot-like core resulting in an isotropic structure. Depending on dendron generation, the polymers differ in thickness as the atomic force microscopy image shows (Figure 2). Neutral and charged dendronized polymers are highly soluble in organic solvents and in water, respectively.
|
|
Langer is widely regarded for his contributions to medicine and biotechnology. He is considered a pioneer of many new technologies, including controlled release systems and transdermal delivery systems, which allow the administration of drugs or extraction of analytes from the body through the skin without needles or other invasive methods. Langer worked with Judah Folkman at Boston Children's Hospital to isolate the first angiogenesis inhibitor, a macromolecule to block the spread of blood vessels in tumors.Cooke, Robert; Koop, C Everett (2001).
|
|
WaTx is a macromolecule with an estimated weight of 3.86 kDa, which consists of 33 amino-acid residues. Its amino-acid sequence is as follows: : The pattern of cysteine residues in the amino acid sequence, which is underlined above, indicates an independent Cys1-Cys4, Cys2-Cys3 disulfide bonding pattern. The two disulfide bridges connect two parallel α-helices with a β-turn. The disulfide bonding pattern stabilizes the rigid and compact helical hairpin structure at two points, contributing to the stable tertiary structure of the protein.
|
|
The term, introduced by Walther Flemming, has multiple meanings: # Simple and concise definition: Chromatin is a macromolecular complex of a DNA macromolecule and protein macromolecules (and RNA). The proteins package and arrange the DNA and control its functions within the cell nucleus. # A biochemists’ operational definition: Chromatin is the DNA/protein/RNA complex extracted from eukaryotic lysed interphase nuclei. Just which of the multitudinous substances present in a nucleus will constitute a part of the extracted material partly depends on the technique each researcher uses.
|
|
The structure of part of a DNA double helix Hydrogen bonding between guanine and cytosine, one of two types of base pairs in DNA In these macromolecules, bonding between parts of the same macromolecule cause it to fold into a specific shape, which helps determine the molecule's physiological or biochemical role. For example, the double helical structure of DNA is due largely to hydrogen bonding between its base pairs (as well as pi stacking interactions), which link one complementary strand to the other and enable replication.
|
|
A reagentless biosensor can monitor a target analyte in a complex biological mixture without additional reagent. Therefore, it can function continuously if immobilized on a solid support. A fluorescent biosensor reacts to the interaction with its target analyte by a change of its fluorescence properties. A Reagentless Fluorescent biosensor (RF biosensor) can be obtained by integrating a biological receptor, which is directed against the target analyte, and a solvatochromic fluorophore, whose emission properties are sensitive to the nature of its local environment, in a single macromolecule.
|
|
Hence, peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. A polypeptide that contains more than approximately fifty amino acids is known as a protein. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, or to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues.
|
|
In clinical diagnosis, the heterophile antibody test specifically refers to a rapid test for antibodies produced against the Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis. Heterophile antibodies can cause significant interference in any immunoassay.An immunoassay is a biochemical test, frequently used in medical diagnostic testing, that measures the presence or concentration of a macromolecule in a solution through the use of an antibody or immunoglobulin. The presence of a heterophile antibody is characterized by broad reactivity with antibodies of other animal species (which are often the source of the assay antibodies).
|
|
Deoxyribonucleic acid is a molecule that carries most of the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids; alongside proteins and complex carbohydrates, they are one of the three major types of macromolecule that are essential for all known forms of life. Most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are known as polynucleotides since they are composed of simpler units called nucleotides.
|
|
Molecular biology is the process of synthesis and regulation of a cell's DNA, RNA, and protein. Molecular biology consists of different techniques including Polymerase chain reaction, Gel electrophoresis, and macromolecule blotting to manipulate DNA. Polymerase chain reaction is done by placing a mixture of the desired DNA, DNA polymerase, primers, and nucleotide bases into a machine. The machine heats up and cools down at various temperatures to break the hydrogen bonds binding the DNA and allows the nucleotide bases to be added onto the two DNA templates after it has been separated.
|
|
Simplified diagram of cytoplasmic protein degradation by the proteasome, transport into endoplasmic reticulum by TAP complex, loading on MHC class I, and transport to the surface for presentation The peptides are generated mainly in the cytosol by the proteasome. The proteasome is a macromolecule that consists of 28 subunits, of which half affect proteolytic activity. The proteasome degrades intracellular proteins into small peptides that are then released into the cytosol. Proteasomes can also ligate distinct peptide fragments (termed spliced peptides), producing sequences that are noncontiguous and therefore not linearly templated in the genome.
|
|
Structural signatures, also called fingerprints, are macromolecule pattern representations that can be used to infer similarities and differences. Comparisons among a large set of proteins using RMSD still is a challenge due to the high computational cost of structural alignments. Structural signatures based on graph distance patterns among atom pairs have been used to determine protein identifying vectors and to detect non-trivial information. Furthermore, algebra linear and machine learning can be used for clustering protein signatures, detecting protein- ligand interactions, predicting ΔΔG, and proposing mutations based on Euclidean distance.
|
|
End groups are an important aspect of polymer synthesis and characterization. In polymer chemistry, end groups are functionalities or constitutional units that are at the extremity of a macromolecule or oligomer (IUPAC).IUPAC Gold Book, "end-group" In polymer synthesis, like condensation polymerization and free-radical types of polymerization, end-groups are commonly used and can be analyzed for example by nuclear magnetic resonance (NMR) to determine the average length of the polymer. Other methods for characterization of polymers where end-groups are used are mass spectrometry and vibrational spectrometry, like infrared and Raman spectrometry.
|
|
IMOD is an open-source, cross-platform suite of modeling, display and image processing programs used for 3D reconstruction and modeling of microscopy images with a special emphasis on electron microscopy data. IMOD has been used across a range of scales from macromolecule structures to organelles to whole cells and can also be used for optical sections. Included in IMOD are tools for image reconstruction, image segmentation, 3D mesh modeling and analysis of 2D and 3D data. IMOD was developed at the Boulder Laboratory for 3-D Electron Microscopy of Cells.
|
|
Chronic administration of corticosteroids decreases 5-HT1A receptor binding, 5-HT2 receptor binding, serotonin levels, and expression of neural cell adhesion molecule (a cell- surface macromolecule involved in regulating aspects of synapse stabilization). These changes indicate structural change follows stress hormone elevation. Studies of dendritic morphological changes indicate that elevation of stress hormones in layer II-III of the prefrontal cortex causes no observable change in the structure or distribution of basal dendrites. The apical dendrites, however, show a significant redistribution in stress-hormone treated animal brains, which is measured using Scholl analysis.
|
|
Lignin is a complex polyphenolic macromolecule composed mainly of beta-O4-aryl linkages. After cellulose, lignin is the second most abundant biopolymer and is one of the primary structural components of most plants. It contains subunits derived from p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol and is unusual among biomolecules in that it is racemic. The lack of optical activity is due to the polymerization of lignin which occurs via free radical coupling reactions in which there is no preference for either configuration at a chiral center.
|
|
However, thermodynamic breakdown of the free-energy gain due to osmolyte addition showed the effect is in fact enthalpically driven, whereas entropy can even be disfavorable. For many cases, the molecular origin of this enthalpically driven depletion force can be traced to an effective "soft" repulsion in the potential of mean force between macromolecule and cosolute. Both Monte-Carlo simulations and a simple analytic model demonstrate that when the hard-core potential (as in Asakura and Oosawa's model) is supplemented with an additional repulsive "softer" interaction, the depletion force can become enthalpically dominated.
|
|
In living cells, signals are processed by networks of proteins that can act as complex computational devices. These networks rely on the ability of single proteins to exist in a variety of functionally different states achieved through multiple mechanisms, including post-translational modifications, ligand binding, conformational change, or formation of new complexes. Similarly, nucleic acids can undergo a variety of transformations, including protein binding, binding of other nucleic acids, conformational change and DNA methylation. In addition, several types of modifications can co-exist, exerting a combined influence on a biological macromolecule at any given time.
|
|
A two-dimensional polymer (2DP) is a sheet-like monomolecular macromolecule consisting of laterally connected repeat units with end groups along all edges. This recent definition of 2DP is based on Hermann Staudinger's polymer concept from the 1920s. According to this, covalent long chain molecules ("Makromoleküle") do exist and are composed of a sequence of linearly connected repeat units and end groups at both termini. Moving from one dimension to two offers access to surface morphologies such as increased surface area, porous membranes, and possibly in-plane pi orbital-conjugation for enhanced electronic properties.
|
|
The word kinetic is added to chain length in order to distinguish the number of reaction steps in the kinetic chain from the number of monomers in the final macromolecule, a quantity named the degree of polymerization. In fact the kinetic chain length is one factor which influences the average degree of polymerization, but there are other factors as described below. The kinetic chain length and therefore the degree of polymerization can influence certain physical properties of the polymer, including chain mobility, glass-transition temperature, and modulus of elasticity.
|
|
Zhang Lina founded the Natural Polymer and Polymer Physics Research Group in 1993 and has been committed to fundamental and applied research of biomass resources and natural macromolecular material science. She solved the problem of the poorest soluble biomass macromolecule. The cellulose is a rich renewable resource on the earth, but the use of traditional manufacturing technology can harm the sustainable development of the environment. Zhang broke through the traditional method of polymer dissolution by heating and successfully dissolved cellulose and chitin using NaOH / urea solution at low temperature.
|
|
Equilibrium between cyclic and open-chain form in one ring of maltose In glucose polymers such as starch and starch-derivatives like glucose syrup, maltodextrin and dextrin the macromolecule begins with a reducing sugar, a free aldehyde. When starch has been partially hydrolyzed the chains have been split and hence it contains more reducing sugars per gram. The percentage of reducing sugars present in these starch derivatives is called dextrose equivalent (DE). Glycogen is a highly branched polymer of glucose that serves as the main form of carbohydrate storage in animals.
|
|
Retroviral integrase (IN) is an enzyme produced by a retrovirus (such as HIV) that integrates—forms covalent links between—its DNA (genetic information) into that of the host cell it infects. Retroviral INs are not to be confused with phage integrases (recombinases), such as λ phage integrase, as discussed in site-specific recombination. The macromolecular complex of an IN macromolecule bound to the ends of the viral DNA ends has been referred to as the intasome; IN is a key component in this and the retroviral pre-integration complex.
|
|
While all sabellids and serpulids employ chlorocruorin as an oxygen transport macromolecule, Serpula is the only genus that appears to possess both hemoglobin as well as chlorocruorin. Chlorocruorin is an oxygen-binding hemeprotein whose affinity for oxygen is weaker than that of most hemoglobins. A dichromatic compound, chlorocruorin is noted for appearing green in dilute solutions, though it appears light red when found in concentrated solutions. Its structure is very similar to erythrocruorin, each molecule being composed of more than a hundred interlinked 16-17kDa myoglobin-like subunits arranged in a giant complex with a total weight exceeding 3600kDa.
|
|
DNA is an information storage macromolecule that encodes the complete set of instructions (the genome) that are required to assemble, maintain, and reproduce every living organism. DNA and RNA are both capable of encoding genetic information, because there are biochemical mechanisms which read the information coded within a DNA or RNA sequence and use it to generate a specified protein. On the other hand, the sequence information of a protein molecule is not used by cells to functionally encode genetic information. DNA has three primary attributes that allow it to be far better than RNA at encoding genetic information.
|
|
Fox has likened the amino acid globules to cells, and proposed it bridged the macromolecule to cell transition. However, his hypothesis was later dismissed as proteinoids are not proteins, they feature mostly non-peptide bonds and amino acid cross-linkages not present in living organisms. Furthermore, they have no compartmentalization and there is no information content in the molecules. Although their role as an evolutionary precursor has been superseded, the hypothesis was a catalyst to further investigate other mechanisms that could have brought about abiogenesis, such as the RNA world, PAH world, Iron–sulfur world, and protocell hypotheses.
|
|
There is no reptation motion for polymers with M<10M_{e}, so that the point 10M_{e} is a point of dynamic phase transition. Due to the reptation motion the coefficient of self-diffusion and conformational relaxation times of macromolecules depend on the length of macromolecule as M^{-2} and M^3, correspondingly. The conditions of existence of reptation in the thermal motion of macromolecules of complex architecture (macromolecules in the form of branch, star, comb and others) have not been established yet. The dynamics of shorter chains or of long chains at short times is usually described by the Rouse model.
|
|
I. Theory and experimental method and Polarization of the fluorescence of macromolecules. II. Fluorescent conjugates of ovalbumin and bovine serum albumin. The theory paper (which contains an acknowledgement to F. Perrin for his suggestions) includes an extension of Perrin’s theory of depolarization due to rotation of ellipsoidal molecules. Specifically, Weber showed that Perrin’s complex equations, which required a knowledge of the orientation of the fluorophore’s absorption and emission oscillators with respect to the axis of rotation of the ellipsoid, could be considerably simplified if the fluorophores carrying the oscillators were assumed to be randomly oriented on the macromolecule.
|
|
However, many naturally occurring apparent antigens are actually a mixture of macromolecules (for example, from pathogens, toxins, proteins, or pollen) comprising several epitopes. Contact with a complex antigen such as a virus will stimulate multiple immune responses to the virus' different macromolecules as well as the individual epitopes of each macromolecule. For example, the tetanus toxin is a single protein macromolecular antigen but will stimulate many immune responses due to the tertiary structure of the protein yielding many different epitopes. The toxin that creates the immune response will have an epitope on it that stimulates the response.
|
|
Flory's earliest work in polymer science was in the area of polymerization kinetics at the DuPont Experimental Station. In condensation polymerization, he challenged the assumption that the reactivity of the end group decreased as the macromolecule grew, and by arguing that the reactivity was independent of the size, he was able to derive the result that the number of chains present decreased with size exponentially. In addition polymerization, he introduced the important concept of chain transfer to improve the kinetic equations and remove difficulties in understanding the polymer size distribution. In 1938, after Carothers' death, Flory moved to the Basic Science Research Laboratory at the University of Cincinnati.
|
|
Boron in particular has been shown to prefer binding to porphyrin in a 2:1 stoichiometry, primarily due to its small atomic radius, but the Group XIII element will bind in a 1:1 ratio with corrole, a macromolecule with a structure similar to porphyrin but with a smaller N4 pocket. Boron porphyrins are of interest because of the unique geometric environment to which both boron and porphyrin are subjected upon B-N(pyrrole) bond formation. These new geometric motifs lead to novel reactivity, one of the most surprising examples being sterically-induced reductive coupling. Possible applications for boron porphyrins include BNCT delivery agents and OLED devices.
|
|
In polymer physics, the coil–globule transition is the collapse of a macromolecule from an expanded coil state through an ideal coil state to a collapsed globule state, or vice versa. The coil–globule transition is of importance in biology due to the presence of coil-globule transitions in biological macromolecules such as proteins and DNA. It is also analogous with the swelling behavior of a crosslinked polymer gel and is thus of interest in biomedical engineering for controlled drug delivery. A particularly prominent example of a polymer possessing a coil-globule transition of interest in this area is that of Poly(N-isopropylacrylamide)(PNIPAAm).
|
|
Bathsheba Grossman (born 1966) is an American artist who creates sculptures using computer-aided design and three-dimensional modeling, with metal printing technology to produce sculpture in bronze and stainless steel. Her bronze sculptures are primarily mathematical in nature, often depicting intricate patterns or mathematical oddities (for instance, a figure with only one side but three edges). Her website also has crystals that have been laser etched with three-dimensional patterns, including models of nearby stars, the DNA macromolecule, and the Milky Way Galaxy. Grossman's works have featured in art galleries around the world, as well as The New York Times, and the television series Numb3rs and Heroes.
|
|
However, there are still major challenges with non-fullerene acceptors, including the low charge carrier mobilities of small molecule acceptors, and that the sheer number of possible molecules is overwhelming for the research community. Small molecules are also being heavily researched to act as donor materials, potentially replacing polymeric donors. Since small molecules do not vary in molecular weights the way polymers do, they would require less purification steps and are less susceptible to macromolecule defects and kinks that can create trap states leading to recombination. Recent research has shown that high- performing small molecular donor structures tend to have planar 2-D structures and can aggregate or self assemble.
|
|
An immunoassay is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoassay is often referred to as an "analyte" and is in many cases a protein, although it may be other kinds of molecules, of different size and types, as long as the proper antibodies that have the adequate properties for the assay are developed. Analytes in biological liquids such as serum or urine are frequently measured using immunoassays for medical and research purposes. Immunoassays come in many different formats and variations.
|
|
Allostery is the most direct and efficient way for regulation of biological macromolecule function induced by the binding of a ligand at an allosteric site topographically distinct from the orthosteric site. Due to the inherent high receptor selectivity and lower target-based toxicity, it is also expected to play a more positive role in drug discovery and bioengineering, leading to rapid growth on allosteric findings. Allosteric Database (ASD) provides a central resource for the display, search and analysis of the structure, function and related annotation for allosteric molecules. Currently, ASD contains allosteric proteins from more than 100 species and modulators in three categories (activators, inhibitors, and regulators).
|
|
This can produce an electropherogram such as the one in Figure 1, where length is related to time at which the samples pass the detector. A marker is a sample of known size run along with the sample so that the actual size of the rest of the sample can be known by comparing their running distance/time to be relative to this marker. RNA is a biological macromolecule made of sugars and nitrogenous bases that plays a number of crucial roles in all living cells. There are several subtypes of RNA, with the most prominent in the cell being tRNA (transfer RNA), rRNA (ribosomal RNA), and mRNA (messenger RNA).
|
|
TTGE profiles representing the bifidobacterial diversity of fecal samples from two healthy volunteers (A and B) before and after AMC (Oral Amoxicillin- Clavulanic Acid) treatment Denaturing gels are run under conditions that disrupt the natural structure of the analyte, causing it to unfold into a linear chain. Thus, the mobility of each macromolecule depends only on its linear length and its mass-to-charge ratio. Thus, the secondary, tertiary, and quaternary levels of biomolecular structure are disrupted, leaving only the primary structure to be analyzed. Nucleic acids are often denatured by including urea in the buffer, while proteins are denatured using sodium dodecyl sulfate, usually as part of the SDS-PAGE process.
|
|
Here, the electrostatic surface emphasizes the electron deficiency of the sulfur atom, suggesting interactions in which it might engage, and chemical reactions it might undergo. An example of a 3D, space-filling model of a very complex macromolecule, a protein, the cell membrane-spanning β2 adrenoreceptor, a G protein-coupled receptor, in this image, viewed as if looking down onto the extracellular surface. The electrostatic potential surface was applied to a model with atom positions determined by crystallography (PDB code 2RH1); the electrostatic surface was computed using Adaptive Poisson-Boltzmann Solver (APBS) freeware.Baker, N.A., Sept, D., Joseph, S., Holst, M.J. & McCammon, J.A., 2001, "Electrostatics of nanosystems: Application to microtubules and the ribosome," Proc. Natl. Acad. Sci.
|
|
By the measurement of decrease in turbidity of M. lysodeikticus by incubating it with lysozyme, enzymatic activity can be evaluated. 7.5 μL of 0.1 - 1 mg/mL proteins is added to 200 μL of M. lysodeikticus at its optical density (OD) of 1.7 AU, and the mixture is measured at 450 nm periodically for reaction rate calculation. On the contrary to the result from glycol chitosan enzymatic activity, the increasing degree of PEGylation decreased the enzymatic activity. This difference in the trend of the enzymatic activity can be due to PEGylation to free lysine causing steric hindrance and subsequently preventing from forming enzyme-substrate complex in the case of reacting with macromolecule, such as M. lysodeikticus.
|
|
A restriction enzyme or restriction endonuclease is a special type of biological macromolecule that functions as part of the "immune system" in bacteria. One special kind of restriction enzymes is the class of "homing endonucleases", these being present in all three domains of life, although their function seems to be very different from one domain to another. The classical restriction enzymes cut up, and hence render harmless, any unknown (non-cellular) DNA that enters a bacterial cell as a result of a viral infection. They recognize a specific DNA sequence, usually short (3 to 8 bp), and cut it, producing either blunt or overhung ends, either at or nearby the recognition site.
|
|
Because protein structures are composed of amino acids whose side chains are linked by a common protein backbone, a number of different possible subsets of the atoms that make up a protein macromolecule can be used in producing a structural alignment and calculating the corresponding RMSD values. When aligning structures with very different sequences, the side chain atoms generally are not taken into account because their identities differ between many aligned residues. For this reason it is common for structural alignment methods to use by default only the backbone atoms included in the peptide bond. For simplicity and efficiency, often only the alpha carbon positions are considered, since the peptide bond has a minimally variant planar conformation.
|
|
Maintenance of the minimum-image convention also generally requires that a spherical cutoff radius for nonbonded forces be at most half the length of one side of a cubic box. Even in electrostatically neutral systems, a net dipole moment of the unit cell can introduce a spurious bulk-surface energy, equivalent to pyroelectricity in polar crystals. The size of the simulation box must also be large enough to prevent periodic artifacts from occurring due to the unphysical topology of the simulation. In a box that is too small, a macromolecule may interact with its own image in a neighboring box, which is functionally equivalent to a molecule's "head" interacting with its own "tail".
|
|
Type I collagen is the most abundant structural macromolecule within the vertebrate body and also represents the most abundant collagen found within various collagen fibrils There are immense differences in the types of collagen fibrils that exist within the body. For instance, fibrils within the tendon vary in width and are banded into aggregates that form fibril bundles that resist forces of tension within one dimension. Similarly, fibrils that form the translucent corneal stromal matrix form orthogonal sheets and withstand the force of traction in two dimensions. These two structurally different collagen fibrils are speculated to be formed from the same molecules with type I collagen being the primary collagen found within both structures.
|
|
The early work in Tirrell's career focused on the behavior of macromolecules in physically confined spaces, in which both the structure and motion of the macromolecule are constrained and distorted by the confining boundaries. For example, the apparent viscosity of a macromolecular solution can be lower because the centers-of-mass of the macromolecules cannot get close to the wall, giving rise to a low viscosity depletion layer (a similar phenomenon occurs, albeit at larger scales, in blood flow in narrow vessels). Tirrell was responsible for developing a quantitative, predictive theoretical picture of this type of phenomenon and comparing it with experimental rheological results. His papers describing this research have collectively been cited more than 1000 times.
|
|
This yielded to macromolecular theory, the term macromolecule introduced by German chemist Hermann Staudinger in 1922 (Morange p 12). cell biology aroseCell biology emerged principally at Rockefeller Institute through new technology (electron microscope and ultracentrifuge) and new techniques (cell fractionation and advancements in staining and fixation). and established existence of cell organelles besides the nucleus. Launched in the late 1930s, the molecular biology research program cracked a genetic code in the early 1960s and then converged with cell biology as cell and molecular biology, its breakthroughs and discoveries defying DN model by arriving in quest not of lawlike explanation but of causal mechanisms.Bechtel, Discovering Cell Mechanisms (Cambridge U P, 2006), esp pp 24–25.
|
|
They primarily occur in areas of the chromosomes that are undergoing DNA replication and interfere with cellular processes. The advancement in structure-identification methods has progressed, and the addition in the ability to measure interactions between DNA and protein is a requirement to fully understand the biochemical processes. The structure of DNA-protein complexes can be mapped by photocrosslinking, which is the photoinduced formation of a covalent bond between two macromolecules or between two different parts of one macromolecule. The methodology involves covalently linking a DNA-binding motif of the target sequence-specific DNA-binding protein with a photoactivatable crosslinking agent capable of reacting with DNA nucleotides when exposed to UV. This method provides information on the interaction between the DNA and protein in the crosslink.
|
|
It was determined that sulfuric acid was to be used as well in the reaction in order to first, catalyze the nitric acid groups so it can allow for the substitution onto the cellulose, and second, allow for the groups to easily and uniformly attach to the fibers, creating a better quality nitrocellulose. The product then must be rinsed to wash away any free acids that did not react with the fibers, dried, and kneaded. During this time, a solution of 50% camphor in alcohol is added, which then changes the macromolecule structure of nitrocellulose into a homogeneous gel of nitrocellulose and camphor. The chemical structure is not well understood, but it is determined that it is one molecule of camphor for each unit of glucose.
|
|
Basil Hiley was born 1935 in Burma, where his father worked for the military of the British Raj. He moved to Hampshire, England, at the age of twelve, where he attended secondary school. His interest in science was stimulated by his teachers at secondary school and by books, in particular The Mysterious Universe by James Hopwood Jeans and Mr Tompkins in Wonderland by George Gamow. Hiley performed undergraduate studies at King's College London.Interview with Basil Hiley conducted by Olival Freire on January 11, 2008, Oral History Transcript, Niels Bohr Library & Archives, American Institute of Physics He published a paper in 1961 on the random walk of a macromolecule, followed by further papers on the Ising model, and on lattice constant systems defined in graph theoretical terms.
|
|
The term macromolecule (macro- + molecule) was coined by Nobel laureate Hermann Staudinger in the 1920s, although his first relevant publication on this field only mentions high molecular compounds (in excess of 1,000 atoms). At that time the term polymer, as introduced by Berzelius in 1832, had a different meaning from that of today: it simply was another form of isomerism for example with benzene and acetylene and had little to do with size. Usage of the term to describe large molecules varies among the disciplines. For example, while biology refers to macromolecules as the four large molecules comprising living things, in chemistry, the term may refer to aggregates of two or more molecules held together by intermolecular forces rather than covalent bonds but which do not readily dissociate.
|
|
SUR LA COMPOSITION DE QUELQUES SUBSTANCES ANIMALES Mulder "was the first to propose a theory concerning the causes of the differences between albumin, casein, and fibrin, and other substances more or less similar to them in physical properties and in their chemical behavior when exposed to reagents. Analyses of these substances showed that their percentage contribution with respect to carbon, hydrogen, nitrogen and oxygen were so similar as to suggest that they contain one common radical."Elmer McCollum (1957) A History of Nutrition, chapter 4: Knowledge of Albuminous Substances, page 48 "The studies of Mulder on albuminous substances", Houghton-Mifflin This radical, a macromolecule, had formula C20 H31 N5 O12 , and was known as protein. The variations in albuminous substances were attributed to peripheral bonds of protein to sulfur and/or phosphorus.
|
|
Most of the cell's macromolecules are affected by ionising radiation, but damage to the DNA macromolecule is most often the cause of cell death, since DNA often contains only a single copy of its genes; proteins, on the other hand, often have several copies so that damage of one will not lead to cell death, and in any case may always be re-synthesized provided the DNA has remained intact.Irradiation of Microbes from Spent Nuclear Fuel Storage Pool Environments Ultraviolet radiation has been used as a germicide by both industry and medicine for more than a century (see Ultraviolet germicidal irradiation). Use of ultraviolet leads to both inactivation and the stimulating of mutations. A case study of an irradiated Escherichia coli population found a growing number of bacteriophage-resistant mutants induced by the light.
|
|
The F1 region also shows significant similarity to hexameric DNA helicases (especially the Rho factor), and the entire enzyme region shows some similarity to -powered T3SS or flagellar motor complexes. The α3β3 hexamer of the F1 region shows significant structural similarity to hexameric DNA helicases; both form a ring with 3-fold rotational symmetry with a central pore. Both have roles dependent on the relative rotation of a macromolecule within the pore; the DNA helicases use the helical shape of DNA to drive their motion along the DNA molecule and to detect supercoiling, whereas the α3β3 hexamer uses the conformational changes through the rotation of the γ subunit to drive an enzymatic reaction. The motor of the FO particle shows great functional similarity to the motors that drive flagella.
|
|
Clock gene mutations, including those to Drosophila's dbt, alter the sensitization of drug-induced locomotor activity after repeated exposure to psychostimulants. Drosophila with mutant alleles of dbt failed to display locomotor sensitization in response to repeated cocaine exposure. Additionally, there is experimental evidence for this gene to function in 13 unique biological processes, including biological regulation, phosphorus metabolic process, establishment of planar polarity, positive regulation of biological process, cellular process, single-organism developmental process, response to stimulus, response to organic substance, sensory organ development, macromolecule modification, growth, cellular component organization or biogenesis, and rhythmic process. The gene's alternative name, discs overgrown, refers to its role as a cell growth regulating gene that has strong effects of cell survival and growth control in imaginal discs, an attribute of the larvae fly stage.
|
|
Discovery Studio is a suite of software for simulating small molecule and macromolecule systems. It is developed and distributed by Dassault Systemes BIOVIA (formerly Accelrys). The product suite has a strong academic collaboration programme, supporting scientific research and makes use of a number of software algorithms developed originally in the scientific community, including CHARMM,Brooks B. R., Brooks III C. L., Mackerell A. D., Nilsson L., Petrella R. J., Roux B., Won Y., Archontis G., Bartels C., Boresch S., Caflisch A., Caves L., Cui Q., Dinner A. R., Feig M., Fischer S., Gao J., Hodoscek M., Im W., Kuczera K., Lazaridis T., Ma J., Ovchinnikov V., Paci E., Pastor R. W., Post C. B., Pu J. Z., Schaefer M., Tidor B., Venable R. M., Woodcock H. L., Wu X., Yang W., York D. M. and Karplus M. CHARMM: The Biomolecular simulation Program, J. Comput. Chem. 2009, 30, 1545-1615.
|
|
Molecular demons or molecular machines either biological or artificially constructed are continuously pushed around by the random thermal motion in a direction that sometimes violates the law. When this happens and the gliding back of the macromolecule from the movement it had made or the conformational change it underwent to its original state can be prevented, as is the case with molecular demons, the molecule works as a ratchet; it is possible to observe for example the creation of a gradient of ions or other molecules across the cell membrane, the movement of motor proteins along filament proteins or also the accumulation of products deriving from an enzymatic reaction. Even some artificial molecular machines and experiments are capable of forming a ratchet apparently defying the second law of thermodynamics. All these molecular demons have to be reset to their original state consuming external energy that is subsequently dissipated as heat.
|
|
Representations of how star shaped polymers are typically shown Star-shaped polymers are the simplest class of branched polymers with a general structure consisting of several (at least three) linear chains connected to a central core. The core, or the center, of the polymer can be an atom, molecule, or macromolecule; the chains, or "arms", consist of variable-length organic chains. Star-shaped polymers in which the arms are all equivalent in length and structure are considered homogeneous, and ones with variable lengths and structures are considered heterogeneous. Star-shaped polymers' unique shape and associated properties, such as their compact structure, high arm density, efficient synthetic routes, and unique rheological properties make them promising tools for use in drug delivery, other biomedical applications, thermoplastics, and nanoelectronicsDrew C. Forman ; Florian Wieberger ; Andre Gröschel ; Axel H. E. Müller ; Hans-Werner Schmidt ; Christopher K. Ober; Comparison of star and linear ArF resists. Proc.
|
|
Because it is a small, stable protein whose structure had been determined at high resolution by 1975, it was the first macromolecule of scientific interest to be simulated using molecular dynamics computation, in 1977 by J. Andrew McCammon and Bruce Gelin, in the Karplus group at Harvard. That study confirmed the then-surprising fact found in the NMR work that even well-packed aromatic sidechains in the interior of a stable protein can flip over rather rapidly (microsecond to millisecond time scale). Rate constants were determined by NMR for the hydrogen exchange of individual peptide NH groups along the chain, ranging from too fast to measure on the most exposed surface to many months for the most buried hydrogen-bonded groups in the center of the β sheet, and those values also correlate fairly well with degree of motion seen in the dynamics simulations. BPTI was important in the development of knowledge about the process of protein folding, the self- assembly of a polypeptide chain into a specific arrangement in 3D.
|
|
In 1953, Francis Crick, James Watson, Maurice Wilkins and Rosalind Franklin discovered the double helix structure of the DNA macromolecule. Gamow attempted to solve the problem of how the ordering of four different bases (adenine, cytosine, thymine and guanine) in DNA chains might control the synthesis of proteins from their constituent amino acids. Crick has said that Gamow's suggestions helped him in his own thinking about the problem. As related by Crick,Crick, Francis "What Mad Pursuit" (Basic Books 1998), Chap.8 The Genetic Code Gamow observed that the 43 = 64 possible permutations of the four DNA bases, taken three at a time, would be reduced to 20 distinct combinations if the order was irrelevant. The twenty distinct combinations are:(3A)(3C)(3G)(3T),(ACG)(ACT)(AGT)(CGT),(2A,C)(2A,G)(2A,T)(2C,A)(2C,G)(2C,T)(2G,A)(2G,C)(2G,T)(2T,A)(2T,C)(2T,G).. Gamow proposed that these 20 combinations might code for the twenty amino acids which, he suggested, might well be the sole constituents of all proteins.
|
|
In 1985, the Northwest Normal University set up the Northwest Ethnic Minority Teachers Training Center directly under the Ministry of Education, with the administrative system featuring "Two Plaques, One Leading Board". In 1987, Tibetan Teachers’ Training Center under the State Council was established in the University. Under the commitment of the Ministry of Education, the University has established a good number of institutes and organizations such as the Elementary Education Curriculum Reform Research Center, the Northwest Ethnic Minority Education Development Research Center, the National Key Constructing Base of Training Teachers for Vocational Education, the National Base of Training Teachers for Physical Education, the Mentors’ Training Base for the Ministry of Education, the Key Lab of Eco- Environmental Macromolecule Materials, and the NWNU Chinese Language and Culture Education Base. Under the commitment of the Overseas Chinese Affairs Office of the State Council, and under the commitment of Gansu Province, 25 research institutes such as Gansu Cultural Development Institute and Gansu Educational Development Institute, as well as 4 provincial-level key labs were established.
|
|
He then moved with the protein crystallography group when it was relocated to the Marseille North University Department. It's at the North University Department that he led his first team at the LCCMB lab (Laboratory of Crystallography and Crystallization of Biological Macromolecules) with this becoming one of the key points of his career. Whilst director he moved in 1995 to the Campus of Joseph Aiguier, where LCCMB became AFMB (Architecture et Fonction de Macromolecule Biologiques). He resigned the direction of the AFMB in 2004, with AFMB moving to the Luminy Campus in 2005. Since 2008 he is Head of Marseille-Nice Génopole. • Direction: \- Director of the Laboratory of Crystallography and Crystallization of Biological Macromolecules, URA 1296: 07/01/1990 to 12/31/1995 \- Laboratory Director "Architecture and Function of Biological Macromolecules" (UPR9039 and UMR6098): 1996-2004. • Research management \- Member of the Section 21 of the National Committee (1995–2000) \- Member of the Jury of Admission Department Sciences de la Vie (2000–2002) \- Member of the Scientific Department Sciences de la Vie (2003–2004) • Expertise national or international \- Expert at the Directorate of International Research at CNRS (1998–2000). \- Expert for orders from the research councils in various countries.
|
|