Fig 4.
FtsNSPOR contains a disulfide bond. (A) Closeup view of C252 and C312 (yellow). β-Sheet residues important for septal localization are shown as red stick figures. (B) FtsN contains a disulfide bond. Whole-cell extracts were prepared in Laemmli sample buffer containing (lanes 2 and 4) or lacking (lanes 3 and 5) 5% β-mercaptoethanol and then analyzed by Western blotting with anti-FtsN (top) or anti-FtsQ (bottom). Samples were loaded twice to facilitate visualization of any mobility differences. (C) Western blot showing that FtsN levels are reduced but DamX levels are normal in two dsbA mutants compared to their isogenic wild-type controls. Cells were grown on M9-glucose medium to mid-log phase, and then total cell extracts were prepared and proteins separated by SDS-PAGE (10% polyacrylamide). After transfer to nitrocellulose, proteins were detected with anti-FtsN or anti-DamX antibody. (D) Lengths and widths of wild-type and dsbA mutant strains grown in LB or M9-glucose medium. Cells grown to mid-log phase were fixed with paraformaldehyde, photographed under phase-contrast conditions, and measured using tools in Image-Pro Plus, version 4.1, from Media Cybernetics (Silver Spring, MD). Bars represent the means and standard deviations for at least two (LB medium) or three (M9 medium) experiments in which 170 or more cells were measured.