Noncovalent associations

Miyamoto S and P A Kollman 1993b. What Determines the Strength of Noncovalent Association of Ligands to Proteins in Aqueous Solution Proceedings of the National Academy of Sciences USA 90 8402-8406. 

There are other glycosaminoglycans. Hyaluronic acid [9004-61-9] occurs both free and in noncovalent association with proteoglycan molecules. Heparin [9005-49-6] and heparan sulfate [39403-40-2] also known as heparitin sulfate [9050-30-0] occur in mast cells and in the aorta, Hver, and lungs. 

Enzyme inhibitors are classified in several ways. The inhibitor may interact either reversibly or irreversibly with the enzyme. Reversible inhibitors interact with the enzyme through noncovalent association/dissociation reactions. In contrast, irreversible inhibitors usually cause stable, covalent alterations in the enzyme. That is, the consequence of irreversible inhibition is a decrease in the concentration of active enzyme. The kinetics observed are consistent with this interpretation, as we shall see later. 

Neurotrophins (NGF brain-derived neurotrophic factor, BDNF neurotrophin-3, NT-3 NT-4 NT-6) are important regulators of neural survival, development, function, and plasticity of the vertebrate nervous system [1]. Neurotrophins generally function as noncovalently associated homodimers. They activate two different classes of receptors, through which signaling pathways can be activated, including those mediated by Ras and members of the cdc42/rac/rho G protein families, MAP kinase, PI-3 kinase, and Jun kinase cascades. 

Fraction Fla was chosen for structural purposes due to its better solubility in water and the absence of Xyl. In order to remove noncovalently associated protein, fraction Flap was submitted to sequential shaking cycles with a mixture of chloroform-buthanol, as indicated by Sevag and described by Staub [17]. The fraction was also treated with trichloroacetic acid. In both procedures, coprecipitation of carbohydrate and protein was observed, suggesting strong linkages and a more complex structure. Fla as was submitted to mild acid hydrolysis yielding Flas and Flap (Table VI). 

Noncovalent Association of the Alkylating Agent can Direct Reaction... 

Miyamoto, S. Kollman, P. A., What determines the strength of noncovalent association of ligands to proteins in aqueous solution , Proc. Natl Acad. Sci. USA 1993, 90, 8402-8406. 

The structure of MHC. In the context of antigen recognition by T cells, we are primarily concerned with class I and II MHC molecules. Class III MHC are essentially a part of the complement system. Class I molecules are made up of transmembrane heavy-chain peptide, which is noncovalently associated with the B2 microglobulin (B2m) molecule. Class II, on the other hand, is composed of two smaller transmembrane peptide chains, a and p. The peptides are arranged in domains that are of comparable size to those of the immunoglobulin molecules. 

Self-assembly is the spontaneous organization of molecules into stable, well-defined structures with the driving forces being noncovalent associations. The final structure is normally near or at the thermodynamic equilibrium arrangement allowing it to form spontaneously. Such formations can be done under conditions where defects are either minimized or eliminated. In nature, self-assembly is common as in the folding of proteins, formation of the DNA double helix, etc. 

Applications of reverse proteolysis in the modular assembly of new proteins are rather scarce. This is due to the fact that high-efficiency ligations of two large fragments call for some conformational assistance from prior noncovalent association between them, or some sort of conformational trapping of the product. 

Pectic polysaccharides are classified as those polymers composed mainly of galactosyluronic residues, together with covalently or nonco-valently bound, neutral fractions. Hemicelluloses are polymers that are probably covalently linked to pectin, and noncovalently associated with cellulose it has been proposed that they are capable of strong hydrogen-... 

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