FIG. 3.

Amino acid sequence alignment and domain structure of clostridial collagenases. (A) The amino acid sequences of the putative prepropeptides were aligned with the Blast2 server. The amino acid positions are numbered from the putative translation initiation site. The predicted signal cleavage sites are indicated by a double line. The observed N-terminal sequences are indicated by a single line. The PLGP sequence is underlined. (B to D) The amino acid sequences of the mature collagenases are divided into three segments, and each segment was aligned separately with the Clustal W program. (B) Segment 1; (C) segment 2; (D) segment 3. The duplicated segments are indicated by the letters a and b. The sequences forming the catalytic center are boxed. Identical and similar residues among the three sequences are indicated by asterisks and colons or dots, respectively. (E) Schematic representation of the segmental structure of clostridial collagenases. aa, amino acids.