Binding protein-independent histidine permease mutants. Uncoupling of ATP hydrolysis from transmembrane signaling.
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.
Petronilli
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Department of Molecular and Cell Biology, University of California, Berkeley 94720.
Ames
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GF
D018528:ATP-Binding Cassette Transporters; D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D026923:Amino Acid Transport Systems, Basic; D001120:Arginine / Q000378:metabolism; D001426:Bacterial Proteins; D001693:Biological Transport, Active; D002462:Cell Membrane / Q000378:metabolism; D006868:Hydrolysis; D007700:Kinetics; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D011487:Protein Conformation; D012486:Salmonella typhimurium / Q000378:metabolism; D015398:Signal Transduction; D012995:Solubility
D018528:ATP-Binding Cassette Transporters; D026923:Amino Acid Transport Systems, Basic; D001426:Bacterial Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000244:Adenosine Diphosphate; C043828:histidine permease, Bacteria; D000255:Adenosine Triphosphate; D001120:Arginine