1v08

From Proteopedia

Revision as of 15:12, 5 November 2007

CRYSTAL STRUCTURE OF THE ZEA MAZE BETA-GLUCOSIDASE-1 IN COMPLEX WITH GLUCO-TETRAZOLE

Overview

Plant beta-glucosidases play a crucial role in defense against pests. They, cleave, with variable specificity, beta-glucosides to release toxic, aglycone moieties. The Sorghum bicolor beta-glucosidase isoenzyme Dhr1 has, a strict specificity for its natural substrate dhurrin, (p-hydroxy-(S)-mandelonitrile-beta-D-glucoside), whereas its close, homolog, the maize beta-glucosidase isoenzyme Glu1, which shares 72%, sequence identity, hydrolyzes a broad spectrum of substrates in addition, to its natural substrate, 2-O-beta-D-glucopyranosyl-4-hydroxy-7-methoxy-1,4-benzoxaxin-3-one., Structural data from enzyme.substrate complexes of Dhr1 show that the mode, of aglycone binding differs from that previously observed in the, homologous maize enzyme. Specifically, the data suggest that Asn(259), Phe(261), and Ser(462), located in the aglycone-binding site of S. bicolor, Dhr1, are crucial for aglycone recognition and binding. The tight binding, of the aglycone moiety of dhurrin promotes the stabilization of the, reaction intermediate in which the glycone moiety is in a deformed (1)S(3), conformation within the glycone-binding site, ready for nucleophilic, attack to occur. Compared with the broad specificity maize, beta-glucosidase, this different binding mode explains the narrow, specificity of sorghum dhurrinase-1.

About this Structure

1V08 is a Single protein structure of sequence from Zea mays with NTZ as ligand. Active as Beta-glucosidase, with EC number 3.2.1.21 Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Structural determinants of substrate specificity in family 1 beta-glucosidases: novel insights from the crystal structure of sorghum dhurrinase-1, a plant beta-glucosidase with strict specificity, in complex with its natural substrate., Verdoucq L, Moriniere J, Bevan DR, Esen A, Vasella A, Henrissat B, Czjze M, J Biol Chem. 2004 Jul 23;279(30):31796-803. Epub 2004 May 17. PMID:15148317

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