Myxococcus xanthus is a Gram-negative bacterium that glides over surfaces without the aid of flagella. Two motility systems are used for locomotion: twitch motility, powered by the retraction of Type IV pili, and gliding motility, powered by unknown mechanism(s). Our studies have shown that AgmU, an A-motility protein, is part of a multi-protein complex that spans the cytoplasm, inner membrane and periplasm of M. xanthus. Further investigation revealed that one subpopulation of AgmU decorates a looped continuous helix that rotates clockwise as cells glide forward, reversing its rotation when cells reverse polarity. Inhibitor studies showed that the AgmU helix rotation is driven by proton motive force (PMF) and depends on actin-like MreB cytoskeletal filaments. The AgmU motility complex was found to interact with MotAB homologues. Our data are consistent with a mechanochemical model in which PMF-driven motors, similar to bacterial flagella stator complexes, run along an endless looped helical track, driving rotation of the track; deformation of the cell surface by the AgmU associated proteins creates pressure waves in the slime, pushing cells forward. My current studies focus on the composition and regulation of the gliding engines.