1din
DIENELACTONE HYDROLASE AT 2.8 ANGSTROMS
Structural highlights
FunctionCLCD_PSEKB Ring cleavage of cyclic ester dienelactone to produce maleylacetate.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe structure of dienelactone hydrolase (DLH) from Pseudomonus sp. B13, after stereochemically restrained least-squares refinement at 1.8 A resolution, is described. The final molecular model of DLH has a conventional R value of 0.150 and includes all but the carboxyl-terminal three residues that are crystallographically disordered. The positions of 279 water molecules are included in the final model. The root-mean-square deviation from ideal bond distances for the model is 0.014 A and the error in atomic co-ordinates is estimated to be 0.15 A. DLH is a monomeric enzyme containing 236 amino acid residues and is a member of the beta-ketoadipate pathway found in bacteria and fungi. DLH is an alpha/beta protein containing seven helices and eight strands of beta-pleated sheet. A single 4-turn 3(10)-helix is seen. The active-site Cys123 residues at the N-terminal end of an alpha-helix that is peculiar in its consisting entirely of hydrophobic residues (except for a C-terminal lysine). The beta-sheet is composed of parallel strands except for strand 2, which gives rise to a short antiparallel region at the N-terminal end of the central beta-sheet. The active-site cysteine residue is part of a triad of residues consisting of Cys123, His202 and Asp171, and is reminiscent of the serine/cysteine proteases. As in papain and actinidin, the active thiol is partially oxidized during X-ray data collection. The positions of both the reduced and the oxidized sulphur are described. The active site geometry suggests that a change in the conformation of the native thiol occurs upon diffusion of substrate into the active site cleft of DLH. This enables nucleophilic attack by the gamma-sulphur to occur on the cyclic ester substrate through a ring-opening reaction. Refined structure of dienelactone hydrolase at 1.8 A.,Pathak D, Ollis D J Mol Biol. 1990 Jul 20;214(2):497-525. PMID:2380986[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||||
