SltF mutants. (A) Schematic representation of the various constructs of SltF of R. sphaeroides. (B) Swimming plates for motility assays, with 0.25% soft agar. Shown are wild-type WS8N, SltF1 (ΔsltF mutant), and SltF1/SltF (SltF1 complemented with wild-type sltF) strains, as well as strains of the SltF1 mutant complemented with sltFΔ47, sltFΔ95, and sltFΔ17. (C) Western blot (15% SDS-PAGE gels) analysis of the different sltF versions that were used in this work. Anti-SltF gamma globulins were used for these assays.