Fig. 4: Proposed mechanism of Ca2+-dependent AtMC4 activation.
From: Structural basis for Ca2+-dependent activation of a plant metacaspase
Two rectangular boxes are for p20 (blue) and p10 (orange) domains. The linker domain consists of linker-N (N-term) and linker-C (C-term) separated by residue Lys225. Two catalytic residues Cys139 and His86 are shown as red sticks. Cleavage sites Lys237 and Lys267 were identified in the study; cleavage sites Arg180, Arg190, and Lys210 were from Hander et al.6 and were confirmed in this study. a Inactive form. b, c Initial cleavage at Lys225. d Additional cleavage in the linker-N for partial activation. e Further cleavage in the linker-C for full activation. f Fully activated form.
