1x8d

From Proteopedia

proteopedia linkproteopedia link

Template:STRUCTURE 1x8d

Crystal structure of E. coli YiiL protein containing L-rhamnose

Overview

The crystal structure of Escherichia coli rhamnose mutarotase (YiiL) is completely different from the previously reported structures of the Lactococcus lactis galactose mutarotase and the Bacillus subtilis RbsD (pyranase). YiiL exists as a locally asymmetric dimer, which is stabilized by an intermolecular beta-sheet, various hydrophobic interactions, and a cation-pi interaction with a salt-bridge. The protein folds of YiiL are similar to those of a Streptomyces coelicolor mono-oxygenase and a hypothetical Arabidopsis thaliana protein At3g17210. By assaying the enzymatic activity of six active-site mutants and by comparing the crystal structure-derived active site conformations of YiiL, RbsD, and a galactose mutarotase, we were able to define the amino acid residues required for catalysis and suggest a possible catalytic mechanism for YiiL. Although the active-site amino acid residues of YiiL (His, Tyr, and Trp) differ greatly from those of galactose mutarotase (His, Glu, and Asp), their geometries, which determine the structures of the preferred monosaccharide substrates, are conserved. In addition, the in vivo function of YiiL was assessed by constructing a mutant E.coli strain that carries a yiiL deletion. The presence of the yiiL gene is critical for efficient cell growth only when concentrations of l-rhamnose are limited.

About this Structure

1X8D is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.

Reference

Structural insights into the monosaccharide specificity of Escherichia coli rhamnose mutarotase., Ryu KS, Kim JI, Cho SJ, Park D, Park C, Cheong HK, Lee JO, Choi BS, J Mol Biol. 2005 May 27;349(1):153-62. Epub 2005 Apr 7. PMID:15876375 Page seeded by OCA on Sat May 3 14:41:57 2008