1txk
From Proteopedia
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Crystal structure of Escherichia coli OpgG
Overview
Osmoregulated periplasmic glucans (OPGs) G protein (OpgG) is required for, OPGs biosynthesis. OPGs from Escherichia coli are branched glucans, with a, backbone of beta-1,2 glucose units and with branches attached by beta-1,6, linkages. In Proteobacteria, OPGs are involved in osmoprotection, biofilm, formation, virulence and resistance to antibiotics. Despite their, important biological implications, enzymes synthesizing OPGs are poorly, characterized. Here, we report the 2.5 A crystal structure of OpgG from, E.coli. The structure was solved using a selenemethionine derivative of, OpgG and the multiple anomalous diffraction method (MAD). The protein is, composed of two beta-sandwich domains connected by one turn of 3(10), helix. The N-terminal domain (residues 22-388) displays a 25-stranded, beta-sandwich fold found in several carbohydrate-related proteins. It, exhibits a large cleft comprising many aromatic and acidic residues. This, putative binding site shares some similarities with enzymes such as, galactose mutarotase and glucodextranase, suggesting a potential catalytic, role for this domain in OPG synthesis. On the other hand, the C-terminal, domain (residues 401-512) has a seven-stranded immunoglobulin-like, beta-sandwich fold, found in many proteins where it is mainly implicated, in interactions with other molecules. The structural data suggest that, OpgG is an OPG branching enzyme in which the catalytic activity is located, in the large N-terminal domain and controlled via the smaller C-terminal, domain.
About this Structure
1TXK is a Single protein structure of sequence from Escherichia coli with NA as ligand. Full crystallographic information is available from OCA.
Reference
Structural analysis of Escherichia coli OpgG, a protein required for the biosynthesis of osmoregulated periplasmic glucans., Hanoulle X, Rollet E, Clantin B, Landrieu I, Odberg-Ferragut C, Lippens G, Bohin JP, Villeret V, J Mol Biol. 2004 Sep 3;342(1):195-205. PMID:15313617
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