1jc4
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Crystal Structure of Se-Met Methylmalonyl-CoA Epimerase
OverviewOverview
BACKGROUND: Methylmalonyl-CoA epimerase (MMCE) is an essential enzyme in, the breakdown of odd-numbered fatty acids and of the amino acids valine, isoleucine, and methionine. Present in many bacteria and in animals, it, catalyzes the conversion of (2R)-methylmalonyl-CoA to, (2S)-methylmalonyl-CoA, the substrate for the B12-dependent enzyme, methylmalonyl-CoA mutase. Defects in this pathway can result in severe, acidosis and cause damage to the central nervous system in humans., RESULTS: The crystal structure of MMCE from Propionibacterium shermanii, has been determined at 2.0 A resolution. The MMCE monomer is folded into, two tandem betaalphabetabetabeta modules that pack edge-to-edge to, generate an 8-stranded beta sheet. Two monomers then pack back-to-back to, create a tightly associated dimer. In each monomer, the beta sheet curves, around to create a deep cleft, in the floor of which His12, Gln65, His91, and Glu141 provide a binding site for a divalent metal ion, as shown by, the binding of Co2+. Modeling 2-methylmalonate into the active site, identifies two glutamate residues as the likely essential bases for the, epimerization reaction. CONCLUSIONS: The betaalphabetabetabeta modules of, MMCE correspond with those found in several other proteins, including, bleomycin resistance protein, glyoxalase I, and a family of extradiol, dioxygenases. Differences in connectivity are consistent with the, evolution of these very different proteins from a common precursor by, mechanisms of gene duplication and domain swapping. The metal binding, residues also align precisely, and striking structural similarities, between MMCE and glyoxalase I suggest common mechanisms in their, respective epimerization and isomerization reactions.
About this StructureAbout this Structure
1JC4 is a Single protein structure of sequence from Propionibacterium freudenreichii subsp. shermanii with SO4 as ligand. Active as Methylmalonyl-CoA epimerase, with EC number 5.1.99.1 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of methylmalonyl-coenzyme A epimerase from P. shermanii: a novel enzymatic function on an ancient metal binding scaffold., McCarthy AA, Baker HM, Shewry SC, Patchett ML, Baker EN, Structure. 2001 Jul 3;9(7):637-46. PMID:11470438
Page seeded by OCA on Sat Nov 24 23:26:08 2007