CHARACTERIZATION OF THE SIGNAL-TRANSDUCTION VIA EVGS AND EVGA IN ESCHERICHIA-COLI

evgS and evgA located at 51 min on the Escherichia coli chromosome wer e previously found as a new two-component system, which is highly homo logous to bvgS and bvgA in Bordetella pertussis. In this study, the pu tative phosphorylation and phospho-transferred sites of EvgS and EvgA, respectively, were changed using modified primers during PCR amplific ation of their structural genes, and their functions were analyzed in vivo. The ompC expression was induced in a Delta envZ E. coli in the p resence of pSK-001, which contains evgS and evgA, but was not changed in the presence of pKM18 (evgS721Arg) or pKM12 (evgA52Ala). Moreover, phosphotransfer from phosphorylated EvgS to EvgA was observed in vitro using the membrane fraction containing EvgS and His-tagged EvgA. Thes e results suggested that the signal transduction via EvgS and EvgA inv olves the previously reported phosphorelay in the two-component system via BvgS and BvgA.