FIG. 7.

CrmA inhibits caspase 1 but does not inhibit nsP2 protease activity in vitro. (A) In vitro-translated pIL-1β was digested with caspase 1 in the presence (1 or 5 μl) or absence (−) of purified GST-CrmA protein and then analyzed by SDS–10% PAGE. Cleavage of pIL-1β to the 17.5-kDa mature form (mIL-1β) was inhibited by GST-CrmA but not by GST protein. (B) Labeled in vitro-translated nsP1234 (C481G) was digested with unlabeled in vitro-translated nsP2 protease (P1*2*3) in the presence (3 or 5 μl) or absence (−) of purified GST-CrmA or GST protein alone. Labeled nsP123 and molecular mass standards (in kilodaltons) serve as markers.