1eap
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(New page: 200px<br /> <applet load="1eap" size="450" color="white" frame="true" align="right" spinBox="true" caption="1eap, resolution 2.4Å" /> '''CRYSTAL STRUCTURE OF...)
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Revision as of 07:22, 18 November 2007
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CRYSTAL STRUCTURE OF A CATALYTIC ANTIBODY WITH A SERINE PROTEASE ACTIVE SITE
Overview
The three-dimensional structure of an unusually active hydrolytic antibody, with a phosphonate transition state analog (hapten) bound to the active, site has been solved to 2.5 A resolution. The antibody (17E8) catalyzes, the hydrolysis of norleucine and methionine phenyl esters and is selective, for amino acid esters that have the natural alpha-carbon L configuration., A plot of the pH-dependence of the antibody-catalyzed reaction is, bell-shaped with an activity maximum at pH 9.5; experiments on mechanism, lend support to the formation of a covalent acyl-antibody intermediate., The structural and kinetic data are complementary and support a hydrolytic, mechanism for the antibody that is remarkably similar to that of the, serine proteases. The antibody active site contains a Ser-His dyad, structure proximal to the phosphorous atom of the bound hapten that, resembles two of the three components of the Ser-His-Asp catalytic triad, of serine proteases. The antibody active site also contains a Lys residue, to stabilize oxyanion formation, and a hydrophobic binding pocket for, specific substrate recognition of norleucine and methionine side chains., The structure identifies active site residues that mediate catalysis and, suggests specific mutations that may improve the catalytic efficiency of, the antibody. This high resolution structure of a catalytic, antibody-hapten complex shows that antibodies can converge on active site, structures that have arisen through natural enzyme evolution.
About this Structure
1EAP is a Single protein structure of sequence from Mus musculus with HEP as ligand. Full crystallographic information is available from OCA.
Reference
Crystal structure of a catalytic antibody with a serine protease active site., Zhou GW, Guo J, Huang W, Fletterick RJ, Scanlan TS, Science. 1994 Aug 19;265(5175):1059-64. PMID:8066444
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