2xmz | pdb_00002xmz

STRUCTURE OF MENH FROM S. AUREUS

spinqualitylabelsall models 2xmz, resolution 1.94Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2xmz is a 1 chain structure with sequence from "micrococcus_aureus"_(rosenbach_1884)_zopf_1885 "micrococcus aureus" (rosenbach 1884) zopf 1885. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Activity: 2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase, with EC number 4.2.99.20 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed ABSTRACT: BACKGROUND: MenH (2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase) is a key enzyme in the biosynthesis of menaquinone, catalyzing an unusual 2,5-elimination of pyruvate from 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexadiene-1-carboxylate. RESULTS: The crystal structure of Staphylococcus aureus MenH has been determined at 2 A resolution. In the absence of a complex to inform on aspects of specificity a model of the enzyme-substrate complex has been used in conjunction with previously published kinetic analyses, site-directed mutagenesis studies and comparisons with orthologues to investigate the structure and reactivity of MenH. CONCLUSIONS: The overall basic active site displays pronounced hydrophobic character on one side and these properties complement those of the substrate. A complex network of hydrogen bonds involving well-ordered water molecules serves to position key residues participating in the recognition of substrate and subsequent catalysis. We propose a proton shuttle mechanism, reliant on a catalytic triad consisting of Ser89, Asp216 and His243. The reaction is initiated by proton abstraction from the substrate by an activated Ser89. The propensity to form a conjugated system provides the driving force for pyruvate elimination. During the elimination, a methylene group is converted to a methyl and we judge it likely that His243 provides a proton, previously acquired from Ser89 for that reduction. A conformational change of the protonated His243 may be encouraged by the presence of an anionic intermediate in the active site. Exploiting the high-resolution crystal structure of Staphylococcus aureus MenH to gain insight into enzyme activity.,Dawson A, Fyfe PK, Gillet F, Hunter WN BMC Struct Biol. 2011 Apr 22;11:19. PMID:21513522 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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