1j8v
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(New page: 200px<br /><applet load="1j8v" size="450" color="white" frame="true" align="right" spinBox="true" caption="1j8v, resolution 2.40Å" /> '''Crystal structure of...)
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Revision as of 21:10, 24 November 2007
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Crystal structure of barley beta-D-glucan glucohydrolase isoenzyme Exo1 in complex with 4'-nitrophenyl 3I-thiolaminaritrioside
Overview
Family 3 beta-D-glucan glucohydrolases are distributed widely in higher, plants. The enzymes catalyze the hydrolytic removal of beta-D-glucosyl, residues from nonreducing termini of a range of beta-D-glucans and, beta-D-oligoglucosides. Their broad specificity can be explained by x-ray, crystallographic data obtained from a barley beta-D-glucan glucohydrolase, in complex with nonhydrolyzable S-glycoside substrate analogs and by, molecular modeling of enzyme/substrate complexes. The glucosyl residue, that occupies binding subsite -1 is locked tightly into a fixed position, through extensive hydrogen bonding with six amino acid residues near the, bottom of an active site pocket. In contrast, the glucosyl residue at, subsite +1 is located between two Trp residues at the entrance of the, pocket, where it is constrained less tightly. The relative flexibility of, binding at subsite +1, coupled with the projection of the remainder of, bound substrate away from the enzyme's surface, means that the overall, active site can accommodate a range of substrates with variable spatial, dispositions of adjacent beta-D-glucosyl residues. The broad specificity, for glycosidic linkage type enables the enzyme to perform diverse, functions during plant development.
About this Structure
1J8V is a Single protein structure of sequence from Hordeum vulgare with LAM as ligand. Active as Glucan 1,3-beta-glucosidase, with EC number 3.2.1.58 Full crystallographic information is available from OCA.
Reference
Structural basis for broad substrate specificity in higher plant beta-D-glucan glucohydrolases., Hrmova M, De Gori R, Smith BJ, Fairweather JK, Driguez H, Varghese JN, Fincher GB, Plant Cell. 2002 May;14(5):1033-52. PMID:12034895
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