1h4h
From Proteopedia
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OLIGOSACCHARIDE-BINDING TO FAMILY 11 XYLANASES: BOTH COVALENT INTERMEDIATE AND MUTANT-PRODUCT COMPLEXES DISPLAY 2,5B CONFORMATIONS AT THE ACTIVE-CENTRE
Overview
The glycoside hydrolase sequence-based classification reveals two families, of enzymes which hydrolyse the beta-1,4-linked backbone of xylan, xylanases, termed families GH-10 and GH-11. Family GH-11 xylanases are, intriguing in that catalysis is performed via a covalent intermediate, adopting an unusual (2,5)B (boat) conformation, a conformation which also, fulfils the stereochemical constraints of the oxocarbenium ion-like, transition state. Here, the 1.9 A structure of a nucleophile, E94A, mutant, of the Xyn11 from Bacillus agaradhaerens in complex with xylotriose is, presented. Intriguingly, this complex also adopts the (2,5)B conformation, in the -1 subsite, with the vacant space provided by the Glu-->Ala, mutation allowing the sugar to adopt the alpha-configuration at C1. The, structure of the covalent 2-deoxy-2-fluoroxylobiosyl-enzyme intermediate, has been extended to atomic (1.1 A) resolution.
About this Structure
1H4H is a Single protein structure of sequence from Bacillus agaradhaerens. Active as Endo-1,4-beta-xylanase, with EC number 3.2.1.8 Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Oligosaccharide binding to family 11 xylanases: both covalent intermediate and mutant product complexes display (2,5)B conformations at the active centre., Sabini E, Wilson KS, Danielsen S, Schulein M, Davies GJ, Acta Crystallogr D Biol Crystallogr. 2001 Sep;57(Pt 9):1344-7. Epub 2001, Aug 23. PMID:11526340
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