1v03: Difference between revisions

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.

1V03 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sorghum_bicolor Sorghum bicolor] with BGC, IPH and CCN as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Beta-glucosidase Beta-glucosidase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.21 3.2.1.21] Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1V03 OCA].  

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