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1on3
From Proteopedia
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Transcarboxylase 12S crystal structure: hexamer assembly and substrate binding to a multienzyme core (with methylmalonyl-coenzyme a and methylmalonic acid bound)
Overview
Transcarboxylase from Propionibacterium shermanii is a 1.2 MDa multienzyme complex that couples two carboxylation reactions, transferring CO(2)(-) from methylmalonyl-CoA to pyruvate, yielding propionyl-CoA and oxaloacetate. The 1.9 A resolution crystal structure of the central 12S hexameric core, which catalyzes the first carboxylation reaction, has been solved bound to its substrate methylmalonyl-CoA. Overall, the structure reveals two stacked trimers related by 2-fold symmetry, and a domain duplication in the monomer. In the active site, the labile carboxylate group of methylmalonyl-CoA is stabilized by interaction with the N-termini of two alpha-helices. The 12S domains are structurally similar to the crotonase/isomerase superfamily, although only domain 1 of each 12S monomer binds ligand. The 12S reaction is similar to that of human propionyl-CoA carboxylase, whose beta-subunit has 50% sequence identity with 12S. A homology model of the propionyl-CoA carboxylase beta-subunit, based on this 12S crystal structure, provides new insight into the propionyl-CoA carboxylase mechanism, its oligomeric structure and the molecular basis of mutations responsible for enzyme deficiency in propionic acidemia.
About this Structure
1ON3 is a Single protein structure of sequence from Propionibacterium freudenreichii with , , and as ligands. Active as Methylmalonyl-CoA carboxytransferase, with EC number 2.1.3.1 Full crystallographic information is available from OCA.
Reference
Transcarboxylase 12S crystal structure: hexamer assembly and substrate binding to a multienzyme core., Hall PR, Wang YF, Rivera-Hainaj RE, Zheng X, Pustai-Carey M, Carey PR, Yee VC, EMBO J. 2003 May 15;22(10):2334-47. PMID:12743028
Page seeded by OCA on Thu Feb 21 14:19:34 2008
Categories: Methylmalonyl-CoA carboxytransferase | Propionibacterium freudenreichii | Single protein | Carey, P R. | Hall, P R. | Pustai-Carey, M. | Rivera-Hainaj, R E. | Wang, Y F. | Yee, V C. | Zheng, X. | CD | DXX | MCA | MPD | Carboxyl transferase | Crystal structure | Domain duplication | Multienzyme complex | Transcarboxylase
