Amino acid sequence alignment of the N-terminal region of the type III ATPases and the B subunit of A/V-type ATPases. The red and green bars indicate α-helices and β-strands, respectively. The conserved residues are colored in red. Every ten residues are denoted by asterisks. FliI form Salmonella typhimurium, FliI; V-ATPase B subunit from Enterococcus hirae, EhVB; A-ATPase B subunit from Thermus thermophilus, TtAB; V-ATPase B subunit from Saccharomyces cerevisiae, ScVB; InvC from Salmonella enterica, InvC; Spa47 from Shigella flexneri, Spa47; YscN from Yersinia pestis, YscN; EscN from Escherichia coli O127, EscN.