Phylogenetic tree based on protein sequences of different flagellar motors. The sequences of the proton-driven flagellar motor MotAB from E. coli (ECDH10B_2031, ECDH10B_2030) and of the sodium-driven flagellar motor PomAB from V. cholerae (VC0892, VC0893) were used as reference proteins. Other proteins were selected after BLAST analysis. Subsequently, the selected protein sequences were aligned used Clustal W, and a neighbor joining tree was drawn using MEGA 5. Ac, Acidithiobacillus caldus ATCC 51756; Ae, Alkalilimnicola ehrlichei MLHE-1; Av, Allochromatium vinosum DSM 180; Bh, Bacillus halodurans C125; Bs, Bacillus subtilis strain 168; Ec, Escherichia coli DH10B; Hh, Halorhodospira halophila SL1; Nm, Nitrococcus mobilis NB-231; Ts, Thioalkalivibrio sulfidophilus HLEbGR7; Tv-K90, Thioalkalivibrio sp. K90mix; Va, Vibrio alginolyticus 12G01; Vc, Vibrio cholera O1; Vp, Vibrio parahaemolyticus RIMD2210633. The sequences of Thioalkalivibrio sp. K90mix are shown in bold type. The bar indicates 20% sequence difference. Numbers on the branches indicate percentage bootstrap values from 1000 iterations; only those values are shown that distinguish the different flagellar motors. The CheW sequence of Thioalkalivibrio sp. K90mix (TK90_1183) was used as an outgroup, but was pruned from the tree.