Respiratory chain is required to maintain oxidized states of the DsbA-DsbB disulfide bond formation system in aerobically growing Escherichia coli cells

摘要

DsbA, the disulfide bond catalyst of Esche- richia coli, is a periplasmic protein having a thioredoxin-like Cys-30-Xaa-Xaa-Cys-33 motif. The Cys-30-Cys-33 disulfide is donated to a pair of cysteines on the target proteins. Although DsbA, having high oxidizing potential, is prone to reduction, it is maintained essentially all oxidized in vivo. DsbB, an integral membrane protein having two pairs of essential cysteines, reoxidizes DsbA that has been reduced upon func- tioning. It is not known, however, what might provide the overall oxidizing power to the DsbA-DsbB disulfide bond formation system.