2cel

From Proteopedia

Revision as of 15:01, 30 October 2007

ACTIVE-SITE MUTANT E212Q DETERMINED AT PH 6.0 WITH NO LIGAND BOUND IN THE ACTIVE SITE

Overview

The roles of the residues in the catalytic trio Glu212-Asp214-Glu217 in, cellobiohydrolase I (CBHI) from Trichoderma reesei have been investigated, by changing these residues to their isosteric amide counterparts. Three, mutants, E212Q, D214N and E217Q, were constructed and expressed in T., reesei. All three point mutations significantly impair the catalytic, activity of the enzyme, although all retain some residual activity. On the, small chromophoric substrate CNP-Lac, the kcat values were reduced to, 1/2000, 1/85 and 1/370 of the wild-type activity, respectively, whereas, the KM values remained essentially unchanged. On insoluble crystalline, cellulose, BMCC, no significant activity was detected for the E212Q and, E217Q mutants, whereas the D214N mutant retained residual activity. The, ... [(full description)]

About this Structure

2CEL is a [Single protein] structure of sequence from [Hypocrea jecorina] with NAG and CA as [ligands]. Active as [Cellulose 1,4-beta-cellobiosidase], with EC number [3.2.1.91]. Structure known Active Sites: CAA, CAB, CTA and CTB. Full crystallographic information is available from [OCA].

Reference

Activity studies and crystal structures of catalytically deficient mutants of cellobiohydrolase I from Trichoderma reesei., Stahlberg J, Divne C, Koivula A, Piens K, Claeyssens M, Teeri TT, Jones TA, J Mol Biol. 1996 Nov 29;264(2):337-49. PMID:8951380

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