Ligand binding induces an asymmetrical transmembrane signal through a receptor dimer.
Two ligand (aspartate)-binding pockets are formed at the interface between the subunits of the Tar homodimer, a bacterial chemoreceptor. Using mutant heterodimers of a hybrid receptor, Taz1, which consists of the external domain of Tar and the cytoplasmic domain of EnvZ, we disrupted either one or the other of the two ligand-binding pockets. We found that occupation of only one of the ligand-binding pockets was sufficient for induction of a transmembrane signal, and that the subunit responsible for the binding of the amino group of the ligand transduces the signal.
Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Rutgers, Piscataway 08854.
Y
Y
Yang
H
H
Park
M
M
Inouye
D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002628:Chemoreceptor Cells; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism; D011487:Protein Conformation; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D015398:Signal Transduction; D001616:beta-Galactosidase / Q000096:biosynthesis
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D009097:Multienzyme Complexes; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; C057331:Tar protein, E coli; C072091:Taz1 protein, E coli; D011494:Protein Kinases; C057843:envZ protein, E coli; D010749:Phosphoprotein Phosphatases; D001616:beta-Galactosidase