Abstract
ComEC is a putative channel protein for DNA uptake in Bacillus subtilis and other genetically transformable bacteria. Membrane topology studies suggest a model of ComEC as a multispanning membrane protein with seven transmembrane segments (TMSs), and possibly with one laterally inserted amphipathic helix. We show that ComEC contains an intramolecular disulphide bond in its N-terminal extracellular loop (between the residues C131 and C172), which is required for the stability of the protein, and is probably introduced by BdbDC, a pair of competence-induced oxidoreductase proteins. By in vitro cross-linking using native cysteine residues we show that ComEC forms an oligomer. The oligomerization surface includes a transmembrane segment, TMS-G, near the cytoplasmic C-terminus of ComEC.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Amino Acid Sequence
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Bacillus subtilis / genetics
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Bacillus subtilis / metabolism*
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Cell Membrane / chemistry
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Cell Membrane / metabolism
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Computer Simulation
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Cysteine / chemistry
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism
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Dimerization
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Disulfides / chemistry
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Membrane Proteins / chemistry
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Models, Molecular
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Molecular Sequence Data
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Protein Disulfide Reductase (Glutathione) / metabolism
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Transformation, Bacterial
Substances
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Bacterial Proteins
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DNA-Binding Proteins
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Disulfides
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Membrane Proteins
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BdbC protein, Bacillus subtilis
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BdbD protein, Bacillus subtilis
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Protein Disulfide Reductase (Glutathione)
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Cysteine