Huberman, Tamir; Eisenberg-Domovich, Yael; Gitlin, Gerry; Kulik, Tikva; Bayer, Edward A.; Wilchek, Meir; Livnah, Oded published the artcile< Chicken avidin exhibits pseudo-catalytic properties: biochemical, structural, and electrostatic consequences>, Recommanded Product: (9Z,12Z)-Methyl octadeca-9,12-dienoate, the main research area is avidin streptavidin substrate complex crystal structure conformation hydrogen bond.
Avidin and its bacterial analog streptavidin exhibit similarly high affinities toward the vitamin biotin. The extremely high affinity of these two proteins has been utilized as a powerful tool in many biotechnol. applications. Although avidin and streptavidin have similar tertiary and quaternary structures, they differ in many of their properties. Here we show that avidin enhances the alk. hydrolysis of biotinyl p-nitrophenyl ester, whereas streptavidin protects this reaction even under extreme alk. conditions (pH > 12). Unlike normal enzymic catalysis, the hydrolysis reaction proceeds as a single cycle with no turnover because of the extremely high affinity of the protein for one of the reaction products (i.e. free biotin). The three-dimensional crystal structures of avidin (2 Å) and streptavidin (2.4 Å) complexed with the amide analog, biotinyl p-nitroanilide, as a model for the p-nitrophenyl ester, revealed structural insights into the factors that enhance or protect the hydrolysis reaction. The data demonstrate that several mol. features of avidin are responsible for the enhanced hydrolysis of biotinyl p-nitrophenyl ester. These include the nature of a decisive flexible loop, the presence of an obtrusive arginine 114, and a newly formed critical interaction between lysine 111 and the nitro group of the substrate. The open conformation of the loop serves to expose the substrate to the solvent, and the arginine shifts the p-nitroanilide moiety toward the interacting lysine, which increases the electron withdrawing characteristics and consequent electrophilicity of the carbonyl group of the substrate. Streptavidin lacked such mol. properties, and analogous interactions with the substrate were consequently absent. The information derived from these structures may provide insight into the action of artificial protein catalysts and the evolution of catalytic sites in general.
Journal of Biological Chemistry published new progress about Avidins Role: BAC (Biological Activity or Effector, Except Adverse), BSU (Biological Study, Unclassified), CAT (Catalyst Use), PRP (Properties), BIOL (Biological Study), USES (Uses). 112-63-0 belongs to class esters-buliding-blocks, and the molecular formula is C19H34O2, Recommanded Product: (9Z,12Z)-Methyl octadeca-9,12-dienoate.
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