MotPS is the stator-force generator for motility of alkaliphilic Bacillus, and its homologue is a second functional Mot in Bacillus subtilis.
Ito M, Hicks DB, Henkin TM, Guffanti AA, Powers BD, Zvi L, Uematsu K, Krulwich TA. Mol Microbiol. 2004 Aug; 53(4):1035-49.