1nu3
From Proteopedia
Limonene-1,2-epoxide hydrolase in complex with valpromide
Overview
Epoxide hydrolases are essential for the processing of epoxide-containing compounds in detoxification or metabolism. The classic epoxide hydrolases have an alpha/beta hydrolase fold and act via a two-step reaction mechanism including an enzyme-substrate intermediate. We report here the structure of the limonene-1,2-epoxide hydrolase from Rhodococcus erythropolis, solved using single-wavelength anomalous dispersion from a selenomethionine-substituted protein and refined at 1.2 A resolution. This enzyme represents a completely different structure and a novel one-step mechanism. The fold features a highly curved six-stranded mixed beta-sheet, with four alpha-helices packed onto it to create a deep pocket. Although most residues lining this pocket are hydrophobic, a cluster of polar groups, including an Asp-Arg-Asp triad, interact at its deepest point. Site-directed mutagenesis supports the conclusion that this is the active site. Further, a 1.7 A resolution structure shows the inhibitor valpromide bound at this position, with its polar atoms interacting directly with the residues of the triad. We suggest that several bacterial proteins of currently unknown function will share this structure and, in some cases, catalytic properties.
About this Structure
1NU3 is a Single protein structure of sequence from Rhodococcus erythropolis. Full crystallographic information is available from OCA.
Reference
Structure of Rhodococcus erythropolis limonene-1,2-epoxide hydrolase reveals a novel active site., Arand M, Hallberg BM, Zou J, Bergfors T, Oesch F, van der Werf MJ, de Bont JA, Jones TA, Mowbray SL, EMBO J. 2003 Jun 2;22(11):2583-92. PMID:12773375 Page seeded by OCA on Sat May 3 02:58:47 2008
