Outer membrane-dependent transport systems in Escherichia coli: turnover of TonB function.

摘要: Recent reports demonstrated that the energy-dependent step of vitamin B12 uptake into cells Escherichia coli rapidly declines after cessation either expression tonB gene or general protein synthesis. It is shown here inhibition synthesis results in decline, with similar kinetics, all tonB-dependent processes, including sensitivity to colicins B and Ia, irreversible adsorption phage phi80, siderophore-mediated iron uptake. The role ongoing TonB-dependent reactions on this lability TonB function was investigated. Ferrichrome enterochelin precursor, 2,3-dihydroxybenzoate, caused both a moderate depression activity growing (reversed upon removal siderophore) an acceleration loss following by addition spectinomycin. Strains lacking siderophore systems did not show these responses. suggest consumption product during its action.