MOLECULAR INTERACTION BETWEEN PROTEINS INVOLVED IN EVGAS SIGNAL-TRANSDUCTION OF ESCHERICHIA-COLI

EvgA and EvgS constitute one two-component signal transduction system in Escherichia coil. Although probable signaling domains of these prot eins have been estimated, the molecular mechanism of their inteaction remains to be elucidated. Here, we investigated protein to protein int eractions between EvgA and EvgS and also between the EvgAS system and other related signaling pathways by means of surface plasmon resonance . EvgA and EvgS interacted directly and inhibition of phosphorylation of their functional domains abolished formation of the EvgAS complex. No interaction was observed either between EvgA and Bordetella BvgS or BvgA and EvgS. OmpR, a response regulator for the osmoregulative gene expression of E. coil, had similar but not identical behavior towards EvgS to that of EvgA. These results indicate that interaction between the signaling proteins is closely related to phosphorylation of the f unctional domain of the proteins.