Imitation of Escherichia coli aspartate receptor signaling in engineered dimers of the cytoplasmic domain.
Transmembrane signaling by bacterial chemotaxis receptors appears to require a conformational change within a receptor dimer. Dimers were engineered of the cytoplasmic domain of the Escherichia coli aspartate receptor that stimulated the kinase CheA in vitro. The folding free energy of the leucine-zipper dimerization domain was harnessed to twist the dimer interface of the receptor, which markedly affected the extent of CheA activation. Response to this twist was attenuated by modification of receptor regulatory sites, in the same manner as adaptation resets sensitivity to ligand in vivo. These results suggest that the normal allosteric activation of the chemotaxis receptor has been mimicked in a system that lacks both ligand-binding and transmembrane domains. The most stimulatory receptor dimer formed a species of tetrameric size.
Cochran
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Howard Hughes Medical Institute, Whitehead Institute for Biomedical Research, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA.
Kim
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D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D002628:Chemoreceptor Cells; D002633:Chemotaxis; D003593:Cytoplasm / Q000378:metabolism; D004789:Enzyme Activation; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D000071677:Histidine Kinase; D016350:Leucine Zippers; D008024:Ligands; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008745:Methylation; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011487:Protein Conformation; D011494:Protein Kinases / Q000378:metabolism; D017433:Protein Structure, Secondary; D017459:Receptors, Amino Acid / Q000737:chemistry / Q000378:metabolism*; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D015398:Signal Transduction
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008024:Ligands; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; C057331:Tar protein, E coli; C031959:aspartic acid receptor; D011494:Protein Kinases; D000071677:Histidine Kinase; C000607608:cheA protein, E coli