1pvd
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(New page: 200px<br /><applet load="1pvd" size="450" color="white" frame="true" align="right" spinBox="true" caption="1pvd, resolution 2.3Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 22:02, 20 November 2007
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CRYSTAL STRUCTURE OF THE THIAMIN DIPHOSPHATE DEPENDENT ENZYME PYRUVATE DECARBOXYLASE FROM THE YEAST SACCHAROMYCES CEREVISIAE AT 2.3 ANGSTROMS RESOLUTION
Overview
The crystal structure of pyruvate decarboxylase (EC 4.1.1.1), a thiamin, diphosphate-dependent enzyme isolated from Saccharomyces cerevisiae, has, been determined and refined to a resolution of 2.3 A. Pyruvate, decarboxylase is a homotetrameric enzyme which crystallizes with two, subunits in an asymmetric unit. The structure has been refined by a, combination of simulated annealing and restrained least squares to an R, factor of 0.165 for 46,787 reflections. As in the corresponding enzyme, from Saccharomyces uvarum, the homotetrameric holoenzyme assembly has, approximate 222 symmetry. In addition to providing more accurate atomic, parameters and certainty in the sequence assignments, the high resolution, and extensive refinement resulted in the identification of several tightly, bound water molecules in key structural positions. These water molecules, have low temperature factors and make several hydrogen bonds with protein, residues. There are six such water molecules in each cofactor binding, site, and one of them is involved in coordination with the required, magnesium ion. Another may be involved in the catalytic reaction, mechanism. The refined model includes 1074 amino acid residues (two, subunits), two thiamin diphosphate cofactors, two magnesium ions, associated with cofactor binding and 440 water molecules. From the refined, model we conclude that the resting state of the enzyme-cofactor complex is, such that the cofactor is already deprotonated at the N4' position of the, pyrimidine ring, and is poised to accept a proton from the C2 position of, the thiazolium ring.
About this Structure
1PVD is a Single protein structure of sequence from Saccharomyces cerevisiae with MG and TPP as ligands. Active as Pyruvate decarboxylase, with EC number 4.1.1.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of the thiamin diphosphate-dependent enzyme pyruvate decarboxylase from the yeast Saccharomyces cerevisiae at 2.3 A resolution., Arjunan P, Umland T, Dyda F, Swaminathan S, Furey W, Sax M, Farrenkopf B, Gao Y, Zhang D, Jordan F, J Mol Biol. 1996 Mar 1;256(3):590-600. PMID:8604141
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