Analysis of ATPase activity of SecA–SecYEG cross-linked complexes in detergent solution. Steady-state ATPase activities were measured in TKM buffer (plus 0.03% C₁₂E₉) containing 0.3 µM SecA in the absence or presence of saturating (1 µM) SecY_K268CEG. The cross-linked SecA–SecYEG complexes (A₇₉₄–Y₂₆₈EG or A₇₉₅–Y₂₆₈EG) were analyzed on their own. The results were averaged from three independent experiments. The inset zooms in on the much lower level uncross-linked enzyme.