1rx0

From Proteopedia

Revision as of 14:50, 15 February 2008

Crystal structure of isobutyryl-CoA dehydrogenase complexed with substrate/ligand.

Overview

The acyl-CoA dehydrogenases are a family of mitochondrial flavoproteins, involved in the catabolism of fatty and amino acids. Isobutyryl-CoA, dehydrogenase (IBD) is involved in the catabolism of valine and catalyzes, the conversion of isobutyryl-CoA to methacrylyl-CoA. The crystal structure, of IBD with and without substrate has been determined to 1.76-A, resolution. The asymmetric unit contains a homotetramer with, substrate/product bound in two monomers. The overall structure of IBD is, similar to those of previously determined acyl-CoA dehydrogenases and, consists of an NH2-terminal alpha-helical domain, a medial beta-strand, domain and a C-terminal alpha-helical domain. The enzyme-bound ligand has, been modeled in as the reaction product, methacrylyl-CoA. The location of, Glu-376 with respect to the C-2-C-3 of the bound product and FAD confirms, Glu-376 to be the catalytic base. IBD has a shorter and wider, substrate-binding cavity relative to short-chain acyl-CoA dehydrogenase, permitting the optimal binding of the isobutyryl-CoA substrate. The, dramatic lateral expansion of the binding cavity seen in isovaleryl-CoA, dehydrogenase is not observed in IBD. The conserved tyrosine or, phenylalanine that defines a side of the binding cavity in other acyl-CoA, dehydrogenases is replaced by a leucine (Leu-375) in the current, structure. Substrate binding changes the position of some residues lining, the binding pocket as well as the position of the loop containing the, catalytic glutamate and subsequent helix. Three clinical mutations have, been modeled to the structure. The mutations do not affect substrate, binding but instead appear to disrupt protein folding and/or stability.

Disease

Known diseases associated with this structure: Blau syndrome OMIM:[605956], Crohn disease, susceptibility to OMIM:[605956], Isobutyryl-CoA dehydrogenase deficiency OMIM:[604773], Psoriatic arthritis, susceptibility to OMIM:[605956], Sarcoidosis, early-onset OMIM:[605956]

About this Structure

1RX0 is a Single protein structure of sequence from Homo sapiens with , , and as ligands. Full crystallographic information is available from OCA.

Reference

Structures of isobutyryl-CoA dehydrogenase and enzyme-product complex: comparison with isovaleryl- and short-chain acyl-CoA dehydrogenases., Battaile KP, Nguyen TV, Vockley J, Kim JJ, J Biol Chem. 2004 Apr 16;279(16):16526-34. Epub 2004 Jan 28. PMID:14752098

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