Mutants in the P-loop fail to complement the motility defect of Δ mglBA. Mutations were generated in conserved residues Gly19 (MxH2445), Lys25 (MxH2430) and Thr26 (MxH2410) that define the γ-phosphate interacting region of MglA (P-loop). A. Graphic representation of the MglA protein, showing the relative position of PM1 (dark box). Residues mutated are indicated with an arrow head. B. (upper) Relative swarming of each strain on 1.5% CTPM agar; (lower) relative swarming of each strain on 0.3% CTPM agar. The WT M. xanthus strain DK1622 and ΔmglBA strain DK6204 are shown as the first and second bars respectively. The third bar (B+A+) shows the complemented control MxH2419 (ΔmglBA+pKD100). C. Colony edge morphology of isolated colonies on 1.5% CTPM agar at 100× magnification. Bar = 25 μm. D. Immunoblot showing production of MglA in each strain. PVDF membranes were probed with α-MglA (1:1000) and goat α-rabbit IgG tagged with Alexa Fluor 800 (1:2500).