Bile salts and fatty acids induce the expression of Escherichia coli AcrAB multidrug efflux pump through their interaction with Rob regulatory protein

摘要: Summary AcrAB of Escherichia coli, an archetype among bacterial multidrug efflux pumps, exports extremely wide range substrates including solvents, dyes, detergents and antimicrobial agents. Its expression is regulated by three XylS/AraC family regulators, MarA, SoxS Rob. Although MarA regulation works the alteration their own levels, it was not known how Rob, which constitutively expressed, exerts its regulatory action. We show here that induction AcrAB pump decanoate more lipophilic unconjugated bile salts mediated low-molecular-weight inducers specifically bind to C-terminal, non-DNA-binding domain Induction Rob needed for AcrAB, we suggest act producing conformational alterations in pre-existing as suggested recently (Rosner, Dangi, Gronenborn Martin, J Bacteriol 184: 1407–1416, 2002). Decanoate salts, are present normal habitat E. were further shown make bacteria resistant antibiotics, at least part because pump. Thus, likely coli protecting itself Rob-mediated upregulation against harmful effects fatty acids intestinal tract.