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Sensory transduction in Escherichia coli: a requirement for methionine in sensory adaptation.

Chemotaxis of E. coli is a behavioral response to a change in the concentration of a stimulatory compound. The response is transient; thus, E. coli undergoes sensory adaptation. In this communication, we show that L-methionine is required by E. coli for adaptation to increases in the concentration of chemical attractants, but is not required for the maintenance of the adapted state. When the concentration of the attractant is lowered to its initial level, cells regain their sensitivity to the attractant. This process of deadaptation does not require methionine. We suggest that the methylation of a membrane protein, a reaction previously shown to be involved in chemotaxis [Kort, E.N., Goy, M.F., Larsen, S.H. & Adler J. (1975) Proc. Natl. Acad. Sci. USA 72, 3939-3943] underlies these phenomena.