1rr2
Propionibacterium shermanii transcarboxylase 5S subunit bound to 2-ketobutyric acid
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OverviewOverview
Transcarboxylase is a 1.2 million Dalton (Da) multienzyme complex from, Propionibacterium shermanii that couples two carboxylation reactions, transferring CO(2)(-) from methylmalonyl-CoA to pyruvate to yield, propionyl-CoA and oxaloacetate. Crystal structures of the 5S metalloenzyme, subunit, which catalyzes the second carboxylation reaction, have been, solved in free form and bound to its substrate pyruvate, product, oxaloacetate, or inhibitor 2-ketobutyrate. The structure reveals a dimer, of beta(8)alpha(8) barrels with an active site cobalt ion coordinated by a, carbamylated lysine, except in the oxaloacetate complex in which the, product's carboxylate group serves as a ligand instead. 5S and human, pyruvate carboxylase (PC), an enzyme crucial to gluconeogenesis, catalyze, similar reactions. A 5S-based homology model of the PC carboxyltransferase, domain indicates a conserved mechanism and explains the molecular basis of, mutations in lactic acidemia. PC disease mutations reproduced in 5S result, in a similar decrease in carboxyltransferase activity and crystal, structures with altered active sites.
About this StructureAbout this Structure
1RR2 is a Single protein structure of sequence from Propionibacterium freudenreichii subsp. shermanii with CO and 2KT as ligands. Active as Methylmalonyl-CoA carboxytransferase, with EC number 2.1.3.1 Full crystallographic information is available from OCA.
ReferenceReference
Transcarboxylase 5S structures: assembly and catalytic mechanism of a multienzyme complex subunit., Hall PR, Zheng R, Antony L, Pusztai-Carey M, Carey PR, Yee VC, EMBO J. 2004 Sep 15;23(18):3621-31. Epub 2004 Aug 26. PMID:15329673
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