1on3

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spinqualitylabelsall models 1on3, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

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 CD, MCA, DXX and MPD 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

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