... and the preprotein is translocated by an insertion–deinsertion cycle of SecA intothe SecYEG translocon [8]. Energy for the translocationprocess is provided by ATP hydrolysis by SecA [8,9] and ... Economou, A. , Pogliano, J .A. , Beckwith, J., Oliver, D.B. &Wickner, W. (1995) SecA membrane cycling at SecYEG is drivenby distinct ATP binding and hydrolysis events and is regulated bySecD and ... thanks also go to William Wickner and ArnoldDriessen for providing antibodies against SecY and SecA, respectively.Further, we thank Bauke Oudega for providing strain MM88, andTom Silhavy for...