2ahc

From Proteopedia

Revision as of 06:00, 21 November 2007

Chorismate lyase with inhibitor Vanilate

Overview

Chorismate lyase (CL) removes the pyruvyl group from chorismate to provide, 4-hydroxybenzoate (4HB) for the ubiquinone pathway. We previously reported, the crystal structure at 1.4A resolution of the Escherichia coli CL with, bound 4HB product, showing that the product is bound in an internal cavity, behind two flaps. To provide a more complete basis for understanding CL's, unusual ligand-binding properties and mechanism of action, we now report, four crystal structures of CL mutants and inhibitor complexes, together, with binding and activity measurements and molecular dynamics simulations., First, an ultrahigh resolution (1.0A) crystal structure of the CL*product, complex reveals details of a substrate-sized internal cavity, also behind, the flaps, near the product site. Second, a 2.4A structure of CL complexed, with the inhibitor vanillate shows the flaps partly opened relative to, their product-bound positions. Third, a 2.0A structure of the G90A mutant, with bound product reveals the basis for tighter product binding and, kinetic effects of this active site mutation. Fourth, the combination of, the G90A mutation with the vanillate inhibitor produces a 1.9A structure, containing two inhibitor molecules, one in the product site and the other, in the adjacent cavity. The two sites are connected by a short tunnel that, is partly open at each end, suggesting that CL may operate via a 2-site or, tunnel mechanism.

About this Structure

2AHC is a Single protein structure of sequence from Escherichia coli with VNL as ligand. Full crystallographic information is available from OCA.

Reference

Structural analysis of ligand binding and catalysis in chorismate lyase., Smith N, Roitberg AE, Rivera E, Howard A, Holden MJ, Mayhew M, Kaistha S, Gallagher DT, Arch Biochem Biophys. 2006 Jan 1;445(1):72-80. Epub 2005 Nov 22. PMID:16343413

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