MotA and MotB comprise the stator element of the flagellar motor complex. Required for rotation of the flagellar motor. Probable transmembrane proton channel (By similarity). Each stator complex is composed of 4 MotA and 2 MotB subunits. 2 A subunits and 1 B subunit are thought to form a single ion channel, so that each stator complex contains two channels (By similarity). Belongs to the MotA family.