FIG. 1.

Schematic representations of preproproteinase PrtP from L. lactis (A) and PrtB from L. bulgaricus and four truncated forms (PrtBδ99, PrtBδ168, PrtBδ247, and PrtBδ806) (B). The different domains of the proteinases and the amino acids (D, H, N, and S for PrtB) involved in the active site are indicated. Small bent arrows correspond to primers designed for gene amplification. The thick horizontal bar in the catalytic domain indicates the peptide (amino acids 280 to 467) used for preparation of the anti-PrtB serum. The dashed thick horizontal bars within the C-terminal region correspond to the two imperfect repeats of 59 residues surrounding the degenerated sorting signal LPKKT. The motifs of the B domain are indicated (B2 to B5) to position the truncated PrtBδ806. Amino acids are numbered starting from the amino end of the mature proteinase.