FIGURE 1.

Residues in the periplasmic domain of FtsQ substituted by the cross-linking residue Bpa. The residues that were individually substituted by Bpa are indicated in the surface plot of the structure of FtsQ amino acids 58–260 in dark gray with the following exceptions. Red, position that showed cross-linking biased toward FtsL; blue, position that showed cross-linking biased toward FtsB; purple, position that showed apparently equal cross-linking to both FtsB and FtsL. Three residues, Asp-245 (D), Arg-247 (R), and Gly-251 (G), fully conserved among 246 FtsQ proteins from Gammaproteobacteria are indicated in yellow. A, two side views. B, top view from the supposed peptidoglycan/outer membrane side. The surface plot was created in PyMOL using PDB code 2VH1.