FIGURE 4.

The YidC contact to the lateral gate is maintained in the absence of SecDFYajC. A, the conditional SecDFYajC depletion strain E. coli BL325 expressing SecY(I91pBpa) was grown either in the presence of arabinose for inducing SecDFYajC expression or in the presence of glucose for SecDFYajC depletion. After reaching an A₆₀₀ of 2.0, cells were harvested and INV were isolated by differential centrifugation. INV of both cultures were then separated on SDS-PAGE (approximately 10 μg of protein) and after Western transfer decorated with antibodies against SecD, SecF, SecY, and YidC. B, SecDFYajC containing and SecDFYajC-depleted BL325 cells, which expressed SecY(I91pBpa) were grown as described in A and subsequently kept either in the dark or UV exposed. After cell breakage, SecY was purified as described in the legend to Fig. 2. Approximately 100 μg of protein was loaded on SDS-PAGE and decorated with α-YidC antibodies after Western transfer.