Schematic domain architecture of FtsQ. The cytoplasmic N-terminal domain (cyto), the TMS, and the periplasmic domain are indicated, with the subdomains α, β, and γ indicated in gray (subdomain assignments are according to reference 29). The amino acid sequence of the FtsQ TMS is shown, and the TMS sequences of the mutants studied with mutated amino acids are shown with changed amino acids in bold. wt, wild type.