Csp proteases (Csps) and the subtilase protease family Subtilases are serine proteases that contain a catalytic triad in the order of Asp, His and Ser. Structure analysis reveals that Csps are subtilisin-like proteases with two distinctive functional features: a central jellyroll domain and a retained prodomain. The prodomain adopts a similar fold to the prodomains of related subtilisin-like proteases with the C-terminal region extending deep into the catalytic cleft. However, unlike the majority of subtilisin-like proteases, the prodomain stays bound to the subtilase domain via a network of interactions that result in tighter prodomain binding relative to other subtilases. Finally the prodomain acts as both an intramolecular chaperone and an inhibitor of CspB protease activity [1].

1: Structural and functional analysis of the CspB protease required for Clostridium spore germination. Adams CM, Eckenroth BE, Putnam EE, Doublie S, Shen A; PLoS Pathog. 2013;9:e1003165. PMID:23408892