1v02
From Proteopedia
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'''CRYSTAL STRUCTURE OF THE SORGHUM BICOLOR DHURRINASE 1''' | '''CRYSTAL STRUCTURE OF THE SORGHUM BICOLOR DHURRINASE 1''' | ||
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[[Category: Moriniere, J.]] | [[Category: Moriniere, J.]] | ||
[[Category: Verdoucq, L.]] | [[Category: Verdoucq, L.]] | ||
| - | [[Category: | + | [[Category: Beta-glucosidase]] |
| - | [[Category: | + | [[Category: Dhurrin hydrolysis]] |
| - | [[Category: | + | [[Category: Family gh1]] |
| - | [[Category: | + | [[Category: Hydrolase]] |
| - | [[Category: | + | [[Category: Pest defense]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 11:55:26 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 08:55, 3 May 2008
CRYSTAL STRUCTURE OF THE SORGHUM BICOLOR DHURRINASE 1
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
1V02 is a Protein complex structure of sequences from Sorghum bicolor. 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 Page seeded by OCA on Sat May 3 11:55:26 2008
