FIG 3.

FimV₆₈₉ is a stable and functional fragment. (A) fimV and fimV cyaB-R456L strains were transformed with arabinose-inducible expression vectors encoding full-length FimV (FimV) or a truncated form lacking TPR3 (FimV₆₈₉). As a control, strains were also transformed with empty vector (pB). Cell lysates prepared as described in Materials and Methods from cells grown on LB medium–1.5% agar supplemented with 0.1% (wt/vol) arabinose were resolved on 10% SDS-PAGE and transferred to a nitrocellulose membrane. FimV was visualized by immunoblotting with anti-FimV antiserum. The previously reported anomalous migration pattern of FimV on SDS-PAGE (17, 18) means that the full-length and truncated versions appear similar in mass despite their differences in length. Data are representative of three experiments. (B). A fimV strain that expresses only the cytoplasmic region of the protein (fimV₁₁₉₄ strain) was transformed with arabinose-inducible expression constructs encoding either full-length FimV or a truncation mutant lacking TPR3 (FimV₆₈₉). As a control, the fimV₁₁₉₄ strain was also transformed with empty vector (pB). Twitching motility was determined by stab inoculation of the strains into LB medium–1% agar supplemented with 0.1% (wt/vol) arabinose. Strains were incubated for 16 h, and twitching zones were visualized by removing the agar layer and staining the bacteria with 1% (wt/vol) crystal violet. Motility was measured as the diameter of the stained twitching zone. Scale bar, 1 cm.