1xc4

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Revision as of 03:51, 21 November 2007

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spinqualitylabelsall models 1xc4, resolution 2.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal structure of wild-type tryptophan synthase alpha-subunits from Escherichia coli

Overview

The alpha-subunit of tryptophan synthase (alphaTS) catalyzes the cleavage, of indole-3-glycerol phosphate to glyceraldehyde-3-phosphate and indole, which is used to yield the amino acid tryptophan in tryptophan, biosynthesis. Here, we report the first crystal structures of wild-type, and double-mutant P28L/Y173F alpha-subunit of tryptophan synthase from, Escherichia coli at 2.8 and 1.8A resolution, respectively. The structure, of wild-type alphaTS from E. coli was similar to that of the, alpha(2)beta(2) complex structure from Salmonella typhimurium. As compared, with both structures, the conformational changes are mostly in the, interface of alpha- and beta-subunits, and the substrate binding region., Two sulfate ions and two glycerol molecules per asymmetric unit bind with, the residues in the active sites of the wild-type structure. Contrarily, double-mutant P28L/Y173F structure is highly closed at the window for the, substrate binding by the conformational changes. The P28L substitution, induces the exposure of hydrophobic amino acids and decreases the, secondary structure that causes the aggregation. The Y173F suppresses to, transfer a signal from the alpha-subunit core to the alpha-subunit surface, involved in interactions with the beta-subunit and increases structural, stability.

About this Structure

1XC4 is a Single protein structure of sequence from Escherichia coli with SO4 and GOL as ligands. Active as Tryptophan synthase, with EC number 4.2.1.20 Full crystallographic information is available from OCA.

Reference

Structures of wild-type and P28L/Y173F tryptophan synthase alpha-subunits from Escherichia coli., Jeong MS, Jeong JK, Lim WK, Jang SB, Biochem Biophys Res Commun. 2004 Oct 29;323(4):1257-64. PMID:15451433

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