1fc4

2-AMINO-3-KETOBUTYRATE COA LIGASE2-AMINO-3-KETOBUTYRATE COA LIGASE

Structural highlights 1fc4 is a 2 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: NonStd Res: , Activity: Glycine C-acetyltransferase, with EC number 2.3.1.29 Resources: FirstGlance, OCA, RCSB, PDBsum, TOPSAN Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed 2-Amino-3-ketobutyrate CoA ligase (KBL, EC 2.3.1.29) is a pyridoxal phosphate (PLP) dependent enzyme, which catalyzes the second reaction step on the main metabolic degradation pathway for threonine. It acts in concert with threonine dehydrogenase and converts 2-amino-3-ketobutyrate, the product of threonine dehydrogenation by the latter enzyme, with the participation of cofactor CoA, to glycine and acetyl-CoA. The enzyme has been well conserved during evolution, with 54% amino acid sequence identity between the Escherichia coli and human enzymes. We present the three-dimensional structure of E. coli KBL determined at 2.0 A resolution. KBL belongs to the alpha family of PLP-dependent enzymes, for which the prototypic member is aspartate aminotransferase. Its closest structural homologue is E. coli 8-amino-7-oxononanoate synthase. Like many other members of the alpha family, the functional form of KBL is a dimer, and one such dimer is found in the asymmetric unit in the crystal. There are two active sites per dimer, located at the dimer interface. Both monomers contribute side chains to each active/substrate binding site. Electron density maps indicated the presence in the crystal of the Schiff base intermediate of 2-amino-3-ketobutyrate and PLP, an external aldimine, which remained bound to KBL throughout the protein purification procedure. The observed interactions between the aldimine and the side chains in the substrate binding site explain the specificity for the substrate and provide the basis for a detailed proposal of the reaction mechanism of KBL. A putative binding site of the CoA cofactor was assigned, and implications for the cooperation with threonine dehydrogenase were considered. Three-dimensional structure of 2-amino-3-ketobutyrate CoA ligase from Escherichia coli complexed with a PLP-substrate intermediate: inferred reaction mechanism.,Schmidt A, Sivaraman J, Li Y, Larocque R, Barbosa JA, Smith C, Matte A, Schrag JD, Cygler M Biochemistry. 2001 May 1;40(17):5151-60. PMID:11318637 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

spinqualitylabelsall models 1fc4, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image