Crosstalk between bacterial chemotaxis signal transduction proteins and regulators of transcription of the Ntr regulon: evidence that nitrogen assimilation and chemotaxis are controlled by a common phosphotransfer mechanism.
We demonstrate by using purified bacterial components that the protein kinases that regulate chemotaxis and transcription of nitrogen-regulated genes, CheA and NRII, respectively, have cross-specificities: CheA can phosphorylate the Ntr transcription factor NRI and thereby activate transcription from the nitrogen-regulated glnA promoter, and NRII can phosphorylate CheY. In addition, we find that a high intracellular concentration of a highly active mutant form of NRII can suppress the smooth-swimming phenotype of a cheA mutant. These results argue strongly that sensory transduction in the Ntr and Che systems involves a common protein phosphotransfer mechanism.
Ninfa, AJ; Ninfa, EG; Lupas, AN; Stock, A; Magasanik, B; Stock, J
Proceedings of the National Academy of Sciences of the United States of America
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