Structural Analysis of Escherichia coli OpgG, a Protein Required for the Biosynthesis of Osmoregulated Periplasmic Glucans
Osmoregulated periplasmic glucans (OPGs) G protein (OpgG) is required for OPGs biosynthesis. OPGs from Escherichia coli are branched glucans, with a backbone of β-1,2 glucose units and with branches attached by β-1,6 linkages. In Proteobacteria, OPGs are involved in osmoprotection, biofilm formation...
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Published in | Journal of molecular biology Vol. 342; no. 1; pp. 195 - 205 |
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Main Authors | , , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Elsevier Ltd
03.09.2004
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | Osmoregulated periplasmic glucans (OPGs) G protein (OpgG) is required for OPGs biosynthesis. OPGs from
Escherichia coli are branched glucans, with a backbone of β-1,2 glucose units and with branches attached by β-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
Å 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 β-sandwich domains connected by one turn of 3
10 helix. The N-terminal domain (residues 22–388) displays a 25-stranded β-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 β-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. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0022-2836 1089-8638 |
DOI: | 10.1016/j.jmb.2004.07.004 |