2i8t

From Proteopedia

Revision as of 15:26, 20 March 2008

GDP-mannose mannosyl hydrolase-calcium-GDP-mannose complex

Overview

Diversity in the polysaccharide component of lipopolysaccharide (LPS) contributes to the persistence and pathogenesis of Gram-negative bacteria. The Nudix hydrolase GDP-mannose mannosyl hydrolase (Gmm) contributes to this diversity by regulating the concentration of mannose in LPS biosynthetic pathways. Here, we present seven high-resolution crystal structures of Gmm from the enteropathogenic E. coli strain O128: the structure of the apo enzyme, the cocrystal structure of Gmm bound to the product Mg2+-GDP, two cocrystal structures of precatalytic and turnover complexes of Gmm-Ca2+-GDP-alpha-d-mannose, and three cocrystal structures of an inactive mutant (His-124 --> Leu) Gmm bound to substrates GDP-alpha-d-mannose, GDP-alpha-d-glucose, and GDP-beta-l-fucose. These crystal structures help explain the molecular basis for substrate specificity and promiscuity and provide a structural framework for reconciling previously determined kinetic parameters. Unexpectedly, these structures reveal concerted changes in the enzyme structure that result in the formation of a catalytically competent active site only in the presence of the substrate/product. These structural views of the enzyme may provide a rationale for the design of inhibitors that target the biosynthesis of LPS by pathogenic bacteria.

About this Structure

2I8T is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

Reference

Molecular basis for substrate selectivity and specificity by an LPS biosynthetic enzyme., Zou Y, Li C, Brunzelle JS, Nair SK, Biochemistry. 2007 Apr 10;46(14):4294-304. Epub 2007 Mar 20. PMID:17371001

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