A. SecB fails to restore proOmpA translocation ATPase activity stimulation of SecA(noC-tail) in the presence of TF. proOmpA translocation ATPase activity stimulation (as in Fig. 1C; SecB molar excess over proOmpA indicated). T/M ratio of SecA(noC-tail) in the absence of TF or SecB= 100%; lane 1; all other values were expressed as a % of this value. n= 4 biological replicates; mean values ± SEM. Unpaired parametric t-test, 95% confidence interval: **: p= 0.0048; ****: p < 0.0001. 