1iq6
From Proteopedia
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(R)-HYDRATASE FROM A. CAVIAE INVOLVED IN PHA BIOSYNTHESIS
Overview
The (R)-specific enoyl coenzyme A hydratase ((R)-hydratase) from Aeromonas, caviae catalyzes the addition of a water molecule to trans-2-enoyl, coenzyme A (CoA), with a chain-length of 4-6 carbons, to produce the, corresponding (R)-3-hydroxyacyl-CoA. It forms a dimer of identical, subunits with a molecular weight of about 14,000 and is involved in, polyhydroxyalkanoate (PHA) biosynthesis. The crystal structure of the, enzyme has been determined at 1.5-A resolution. The structure of the, monomer consists of a five-stranded antiparallel beta-sheet and a central, alpha-helix, folded into a so-called "hot dog" fold, with an overhanging, segment. This overhang contains the conserved residues including the, hydratase 2 motif residues. In dimeric form, two beta-sheets are, associated to form an extended 10-stranded beta-sheet, and the overhangs, obscure the putative active sites at the subunit interface. The active, site is located deep within the substrate-binding tunnel, where Asp(31), and His(36) form a catalytic dyad. These residues are catalytically, important as confirmed by site-directed mutagenesis and are possibly, responsible for the activation of a water molecule and the protonation of, a substrate molecule, respectively. Residues such as Leu(65) and Val(130), are situated at the bottom of the substrate-binding tunnel, defining the, preference of the enzyme for the chain length of the substrate. These, results provide target residues for protein engineering, which will, enhance the significance of this enzyme in the production of novel PHA, polymers. In addition, this study provides the first structural, information of the (R)-hydratase family and may facilitate further, functional studies for members of the family.
About this Structure
1IQ6 is a Single protein structure of sequence from Aeromonas punctata with IPA as ligand. Active as Enoyl-CoA hydratase, with EC number 4.2.1.17 Full crystallographic information is available from OCA.
Reference
Crystal structure of the (R)-specific enoyl-CoA hydratase from Aeromonas caviae involved in polyhydroxyalkanoate biosynthesis., Hisano T, Tsuge T, Fukui T, Iwata T, Miki K, Doi Y, J Biol Chem. 2003 Jan 3;278(1):617-24. Epub 2002 Oct 29. PMID:12409309
Page seeded by OCA on Sat Nov 24 22:21:43 2007
