1ydn

Crystal Structure of the HMG-CoA Lyase from Brucella melitensis, Northeast Structural Genomics Target LR35.

spinqualitylabelsall models 1ydn, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1ydn is a 4 chain structure with sequence from Brume. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: CA NonStd Res: MSE Related: 1ydo Gene: GeneID:1197637 (BRUME) Activity: Hydroxymethylglutaryl-CoA lyase, with EC number 4.1.3.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT, 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 The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) lyase catalyzes the terminal steps in ketone body generation and leucine degradation. Mutations in this enzyme cause a human autosomal recessive disorder called primary metabolic aciduria, which typically kills victims because of an inability to tolerate hypoglycemia. Here we present crystal structures of the HMG-CoA lyases from Bacillus subtilis and Brucella melitensis at 2.7 and 2.3 A resolution, respectively. These enzymes share greater than 45% sequence identity with the human orthologue. Although the enzyme has the anticipated triose-phosphate isomerase (TIM) barrel fold, the catalytic center contains a divalent cation-binding site formed by a cluster of invariant residues that cap the core of the barrel, contrary to the predictions of homology models. Surprisingly, the residues forming this cation-binding site and most of their interaction partners are shared with three other TIM barrel enzymes that catalyze diverse carbon-carbon bond cleavage reactions believed to proceed through enolate intermediates (4-hydroxy-2-ketovalerate aldolase, 2-isopropylmalate synthase, and transcarboxylase 5S). We propose the name "DRE-TIM metallolyases" for this newly identified enzyme family likely to employ a common catalytic reaction mechanism involving an invariant Asp-Arg-Glu (DRE) triplet. The Asp ligates the divalent cation, while the Arg probably stabilizes charge accumulation in the enolate intermediate, and the Glu maintains the precise structural alignment of the Asp and Arg. We propose a detailed model for the catalytic reaction mechanism of HMG-CoA lyase based on the examination of previously reported product complexes of other DRE-TIM metallolyases and induced fit substrate docking studies conducted using the crystal structure of human HMG-CoA lyase (reported in the accompanying paper by Fu, et al. (2006) J. Biol. Chem. 281, 7526-7532). Our model is consistent with extensive mutagenesis results and can guide subsequent studies directed at definitive experimental elucidation of this enzyme's reaction mechanism. Crystal structures of two bacterial 3-hydroxy-3-methylglutaryl-CoA lyases suggest a common catalytic mechanism among a family of TIM barrel metalloenzymes cleaving carbon-carbon bonds.,Forouhar F, Hussain M, Farid R, Benach J, Abashidze M, Edstrom WC, Vorobiev SM, Xiao R, Acton TB, Fu Z, Kim JJ, Miziorko HM, Montelione GT, Hunt JF J Biol Chem. 2006 Mar 17;281(11):7533-45. Epub 2005 Dec 5. PMID:16330546 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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