Abstract
Periplasmic permeases consist of a substrate-binding receptor, located in the periplasm, and a membrane-bound complex composed of two integral membrane proteins and two nucleotide-binding proteins. The receptor interacts with the membrane-bound complex, which, upon receiving this signal, is postulated to hydrolyze ATP and translocate the substrate. We show that a class of mutations in the membrane-bound complex of the histidine permease, which allow transport in the absence of the substrate-binding protein, hydrolyze ATP independently from any signal. The data are compatible with the notion that cross-membrane signaling between the liganded periplasmic receptor and the cytoplasmic ATP-binding sites initiates conformational changes leading to ATP hydrolysis and substrate translocation.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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ATP-Binding Cassette Transporters*
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Adenosine Diphosphate / metabolism
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Adenosine Triphosphate / metabolism
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Amino Acid Transport Systems, Basic*
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Arginine / metabolism
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Bacterial Proteins*
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Biological Transport, Active
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Cell Membrane / metabolism
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Hydrolysis
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Kinetics
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Membrane Proteins / genetics
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Membrane Proteins / metabolism*
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Membrane Transport Proteins / genetics
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Membrane Transport Proteins / metabolism*
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Mutation*
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Protein Conformation
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Salmonella typhimurium / metabolism
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Signal Transduction*
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Solubility
Substances
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ATP-Binding Cassette Transporters
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Amino Acid Transport Systems, Basic
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Bacterial Proteins
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Membrane Proteins
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Membrane Transport Proteins
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Adenosine Diphosphate
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histidine permease, Bacteria
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Adenosine Triphosphate
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Arginine