2jib

From Proteopedia

Revision as of 08:46, 3 February 2008

X-RAY STRUCTURE OF OXALYL-COA DECARBOXYLASE IN COMPLEX WITH COENZYME-A

Overview

Despite more than five decades of extensive studies of thiamin diphosphate, (ThDP) enzymes, there remain many uncertainties as to how these enzymes, achieve their rate enhancements. Here, we present a clear picture of, catalysis for the simple nonoxidative decarboxylase, oxalyl-coenzyme A, (CoA) decarboxylase, based on crystallographic snapshots along the, catalytic cycle and kinetic data on active site mutants. First, we provide, crystallographic evidence that, upon binding of oxalyl-CoA, the C-terminal, 13 residues fold over the substrate, aligning the substrate alpha-carbon, for attack by the ThDP-C2 atom. The second structure presented shows a, covalent reaction intermediate after decarboxylation, interpreted as being, nonplanar. Finally, the structure of a product complex is presented. In, accordance with mutagenesis data, no side chains of the enzyme are implied, to directly participate in proton transfer except the glutamic acid, (Glu-56), which promotes formation of the 1',4'-iminopyrimidine tautomer, of ThDP needed for activation.

About this Structure

2JIB is a Single protein structure of sequence from Oxalobacter formigenes with , , , and as ligands. Active as Oxalyl-CoA decarboxylase, with EC number 4.1.1.8 Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Crystallographic snapshots of oxalyl-CoA decarboxylase give insights into catalysis by nonoxidative ThDP-dependent decarboxylases., Berthold CL, Toyota CG, Moussatche P, Wood MD, Leeper F, Richards NG, Lindqvist Y, Structure. 2007 Jul;15(7):853-61. PMID:17637344

Page seeded by OCA on Sun Feb 3 10:46:12 2008