1lkc
From Proteopedia
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Crystal Structure of L-Threonine-O-3-Phosphate Decarboxylase from Salmonella enterica
Overview
The three-dimensional structure of the pyridoxal 5'-phosphate, (PLP)-dependent L-threonine-O-3-phosphate decarboxylase (CobD) from, Salmonella enterica is described here. This enzyme is responsible for, synthesizing (R)-1-amino-2-propanol phosphate which is the precursor for, the linkage between the nucleotide loop and the corrin ring in cobalamin., The molecule is a molecular dimer where each subunit consists of a large, and small domain. Overall the protein is very similar to the members of, the family of aspartate aminotransferases. Indeed, the arrangement of the, ligands surrounding the cofactor and putative substrate binding site are, remarkably close to that observed in histidinol phosphate, aminotransferase, which suggests that this latter enzyme might have been, its progenitor. The only significant differences in structure occur at the, N-terminus, which is approximately 12 residues shorter in CobD and does, not form the same type of interdomain interaction common to other, aminotransferases. CobD is unusual since within the aspartate, aminotransferase subfamily of PLP-dependent enzymes the chemical, transformations are substantially conserved, where the only exceptions are, 1-aminocyclopropane-1-carboxylate synthase and CobD. Although there are a, large number of PLP-dependent amino acid decarboxylases, these are, generally larger and structurally distinct from the members of the, aspartate aminotransferase subfamily of enzymes. The structure of CobD, suggests that the chemical fate of the external aldimine can be redirected, by modifications at the N-terminus of the protein. This study provides, insight into the evolutionary history of the cobalamin biosynthetic, pathway and raises the question of why most PLP-dependent decarboxylases, are considerably larger enzymes.
About this Structure
1LKC is a Single protein structure of sequence from Salmonella enterica with PO4, PLP and EDO as ligands. This structure superseeds the now removed PDB entry 1KUS. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of the L-threonine-O-3-phosphate decarboxylase (CobD) enzyme from Salmonella enterica., Cheong CG, Bauer CB, Brushaber KR, Escalante-Semerena JC, Rayment I, Biochemistry. 2002 Apr 16;41(15):4798-808. PMID:11939774
Page seeded by OCA on Tue Nov 20 20:37:28 2007
