FIG 2.

Schematic representation of the primary structures (A) and SDS-PAGE analysis of recombinant SptC and its derivatives (B). (A) The locations of the active-site residues (D40, H76, and S230) in the subtilisin-like catalytic domain and the N- and C-terminal residues of each region are shown. S, N, and H represent the signal peptide, N-terminal propeptide, and His tag, respectively. (B) Samples of purified proteins were precipitated with TCA and then subjected to SDS-PAGE analysis. The predicted molecular mass (MW) of each protein was calculated based on the amino acid sequence, and the apparent MW was determined by SDS-PAGE analysis.