Abstract
RbsC of Escherichia coli is the hydrophobic membrane component of ribose uptake system classified as the ATP-binding cassette transporter. To understand the structure and function of RbsC, its transmembrane topology was investigated by using 64 RbsC-PhoA fusions isolated either specifically or randomly. In order to confirm the cytoplasmic location of the short C-terminal region (5 amino acids), inside-out or right-side-out membrane vesicles were generated, and the C-terminal region was found to be digested by carboxypeptidase A only in inside-out vesicles. This result is consistent with the model, based on the results of alkaline phosphatase fusions, in which the protein traverses the membrane six times and the N and C termini are exposed to the cytoplasm.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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ATP-Binding Cassette Transporters / chemistry*
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ATP-Binding Cassette Transporters / genetics
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Alkaline Phosphatase
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Amino Acid Sequence
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Carboxypeptidases
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Carboxypeptidases A
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Cell Membrane / physiology
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Cell Membrane / ultrastructure
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Cyclin-Dependent Kinases / chemistry
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Cytoplasm / physiology
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Escherichia coli / genetics
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Escherichia coli / physiology*
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Escherichia coli Proteins*
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Models, Molecular
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Molecular Sequence Data
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Polymerase Chain Reaction
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Protein Structure, Secondary*
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Recombinant Fusion Proteins / chemistry
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Restriction Mapping
Substances
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ATP-Binding Cassette Transporters
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Bacterial Proteins
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Escherichia coli Proteins
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RbsC protein, E coli
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Recombinant Fusion Proteins
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Cyclin-Dependent Kinases
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Alkaline Phosphatase
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phoA protein, E coli
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Carboxypeptidases
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Carboxypeptidases A