Structural and Functional Analysis of the CspB Protease Required for Clostridium Spore Germination
Figure 2
CspB undergoes autoprocessing in a position-dependent manner.
(a) Coomassie staining of recombinant C. perfringens and C. difficile CspB variants. 7.5 µg of each purified CspB variant was resolved by SDS-PAGE on a 4–12% Bis-Tris gel and visualized by Coomassie staining. The P3-P1 residues of the prodomain were mutated to Ala for the YTS/AAA and QTQ/AAA mutants, while the P3-P1 residues were deleted from CspB perfringens in the ΔYTS mutant. The products resulting from autoprocessing are indicated. (b) Sequence alignment of Csp prodomain cleavage sites mapped by Edman sequencing; the Csp perfringens cleavage sites were mapped in a previous study [25]. Completely conserved identical residues are blocked in black with white text, conserved identical residues in grey with white text, and conserved similar residues in light grey.