2nxw

Crystal structure of phenylpyruvate decarboxylase of Azospirillum brasilense

spinqualitylabelsall models 2nxw, resolution 1.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2nxw is a 2 chain structure with sequence from Azospirillum brasilense. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.5Å Ligands: CL, GOL, MG, TPP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function DCIP_AZOBR 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 Phenylpyruvate decarboxylase (PPDC) of Azospirillum brasilense, involved in the biosynthesis of the plant hormone indole-3-acetic acid and the antimicrobial compound phenylacetic acid, is a thiamine diphosphate-dependent enzyme that catalyses the nonoxidative decarboxylation of indole- and phenylpyruvate. Analogous to yeast pyruvate decarboxylases, PPDC is subject to allosteric substrate activation, showing sigmoidal v versus [S] plots. The present paper reports the crystal structure of this enzyme determined at 1.5 A resolution. The subunit architecture of PPDC is characteristic for other members of the pyruvate oxidase family, with each subunit consisting of three domains with an open alpha/beta topology. An active site loop, bearing the catalytic residues His112 and His113, could not be modelled due to flexibility. The biological tetramer is best described as an asymmetric dimer of dimers. A cysteine residue that has been suggested as the site for regulatory substrate binding in yeast pyruvate decarboxylase is not conserved, requiring a different mechanism for allosteric substrate activation in PPDC. Only minor changes occur in the interactions with the cofactors, thiamine diphosphate and Mg2+, compared to pyruvate decarboxylase. A greater diversity is observed in the substrate binding pocket accounting for the difference in substrate specificity. Moreover, a catalytically important glutamate residue conserved in nearly all decarboxylases is replaced by a leucine in PPDC. The consequences of these differences in terms of the catalytic and regulatory mechanism of PPDC are discussed. The crystal structure of phenylpyruvate decarboxylase from Azospirillum brasilense at 1.5 A resolution. Implications for its catalytic and regulatory mechanism.,Versees W, Spaepen S, Vanderleyden J, Steyaert J FEBS J. 2007 May;274(9):2363-75. Epub 2007 Mar 30. PMID:17403037 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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