FIG. 4.

Assembly of SpaD, SpaE, and SpaF requires a specific sortase. (A) Graphic representation of the second gene cluster in the chromosome of C. diphtheriae NCTC13129 that encode sortases (srtB and srtC) and sortase-mediated pilus assemblies (spaDEF). Location of designated genes in the genome is shown by numbers. Arrows indicate the position of predicted promoters as well as the direction of transcription. Corynebacterial strains were treated with muramidase (M) or formic acid (F) or were left untreated (−) prior to extraction with hot SDS sample buffer. Proteins were separated on SDS-PAGE and detected by immunoblotting with α-SpaD (B), α-SpaE (C), or α-SpaF (D). wt, wild type.