FIGURE 3.

The structures/models of the bacterial export and insertion machineries. Export of proteins across the membrane are catalyzed by (A) the Tat complex (resting complex shown) in a folded state (left side) (Habersetzer et al., 2017) or (C) by SecYEG/SecDF/YidC [adapted from Botte et al. (2016) PDB: 5MG3] energized by the SecA motor ATPase (not shown) in an unfolded state. TatA, TatB and TatC is shown in cyan, magenta and green, respectively. SecY, SecE, and SecG is shown in green, red, and magenta; SecD, SecF and YidC are shown in orange, blue and cyan. Membrane protein integration is catalyzed by the SecYEG/SecDF/YidC (C) complex or by the YidC insertase (B) [adapted from Kumazaki et al. (2014b) PDB: 3WVF]. The view is in the plane of the membrane with the periplasmic face at the top and the cytoplasmic face at the bottom.