1ovm
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(New page: 200px<br /><applet load="1ovm" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ovm, resolution 2.65Å" /> '''Crystal structure of...)
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Revision as of 21:06, 20 November 2007
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Crystal structure of Indolepyruvate decarboxylase from Enterobacter cloacae
Overview
The thiamin diphosphate-dependent enzyme indolepyruvate decarboxylase, catalyses the formation of indoleacetaldehyde from indolepyruvate, one, step in the indolepyruvate pathway of biosynthesis of the plant hormone, indole-3-acetic acid. The crystal structure of this enzyme from, Enterobacter cloacae has been determined at 2.65 A resolution and refined, to a crystallographic R-factor of 20.5% (Rfree 23.6%). The subunit of, indolepyruvate decarboxylase contains three domains of open alpha/beta, topology, which are similar in structure to that of pyruvate, decarboxylase. The tetramer has pseudo 222 symmetry and can be described, as a dimer of dimers. It resembles the tetramer of pyruvate decarboxylase, from Zymomonas mobilis, but with a relative difference of 20 degrees in, the angle between the two dimers. Active site residues are highly, conserved in indolepyruvate/pyruvate decarboxylase, suggesting that the, interactions with the cofactor thiamin diphosphate and the catalytic, mechanisms are very similar. The substrate binding site in indolepyruvate, decarboxylase contains a large hydrophobic pocket which can accommodate, the bulky indole moiety of the substrate. In pyruvate decarboxylases this, pocket is smaller in size and allows discrimination of larger vs. smaller, substrates. In most pyruvate decarboxylases, restriction of cavity size is, due to replacement of residues at three positions by large, hydrophobic, amino acids such as tyrosine or tryptophan.
About this Structure
1OVM is a Single protein structure of sequence from Enterobacter cloacae with MG and TPP as ligands. Active as Indolepyruvate decarboxylase, with EC number 4.1.1.74 Full crystallographic information is available from OCA.
Reference
Crystal structure of thiamindiphosphate-dependent indolepyruvate decarboxylase from Enterobacter cloacae, an enzyme involved in the biosynthesis of the plant hormone indole-3-acetic acid., Schutz A, Sandalova T, Ricagno S, Hubner G, Konig S, Schneider G, Eur J Biochem. 2003 May;270(10):2312-21. PMID:12752451
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