Cloning of the C-terminal cytoplasmic fragment of the tar protein and effects of the fragment on chemotaxis of Escherichia coli.
A gene encoding only the C-terminal portion of the receptor-transducer protein Tar of Escherichia coli was constructed. The gene product was detected and localized in the cytoplasmic fraction of the cell by immunoblotting with anti-Tar antibodies. The C-terminal fragments from wild-type and mutant tar genes were characterized in vivo. The C-terminal fragment generated from tar-526, a mutation that results in a dominant "tumble" phenotype, was found to be deamidated and methylated by the CheB and CheR proteins, respectively. The C-terminal fragment derived from a wild-type gene was poorly deamidated, and the C-terminal fragment derived from tar-529, a dominant mutant with a "smooth swimming" phenotype, was not apparently modified. Cells carrying the C-terminal fragment with the tar-526 mutation as the sole receptor-transducer protein showed a high frequency of tumbling and chemotaxis responses to changes in intracellular pH. These results suggest that the cytoplasmic C-terminal fragment of Tar retains some of the functions of the whole protein in vivo.
Oosawa
K
K
Division of Biology, California Institute of Technology, Pasadena 91125.
Mutoh
N
N
Simon
M I
MI
D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics*; D002633:Chemotaxis / Q000187:drug effects*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000187:drug effects*; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D016202:N-Methylaspartate; D010446:Peptide Fragments / Q000235:genetics* / Q000494:pharmacology; D010641:Phenotype
D001426:Bacterial Proteins; D010446:Peptide Fragments; D001224:Aspartic Acid; D016202:N-Methylaspartate