7xn6 | pdb_00007xn6
Cryo-EM structure of CopC-CaM-caspase-3 with ADPR-deacylization
Structural highlights
FunctionCASP3_HUMAN Involved in the activation cascade of caspases responsible for apoptosis execution. At the onset of apoptosis it proteolytically cleaves poly(ADP-ribose) polymerase (PARP) at a '216-Asp-|-Gly-217' bond. Cleaves and activates sterol regulatory element binding proteins (SREBPs) between the basic helix-loop-helix leucine zipper domain and the membrane attachment domain. Cleaves and activates caspase-6, -7 and -9. Involved in the cleavage of huntingtin. Triggers cell adhesion in sympathetic neurons through RET cleavage.[1] [2] Publication Abstract from PubMedProgrammed cell death and caspase proteins play a pivotal role in host innate immune response combating pathogen infections. Blocking cell death is employed by many bacterial pathogens as a universal virulence strategy. CopC family type III effectors, including CopC from an environmental pathogen Chromobacterium violaceum, utilize calmodulin (CaM) as a co-factor to inactivate caspases by arginine ADPR deacylization. However, the molecular basis of the catalytic and substrate/co-factor binding mechanism is unknown. Here, we determine successive cryo-EM structures of CaM-CopC-caspase-3 ternary complex in pre-reaction, transition, and post-reaction states, which elucidate a multistep enzymatic mechanism of CopC-catalyzed ADPR deacylization. Moreover, we capture a snapshot of the detachment of modified caspase-3 from CopC. These structural insights are validated by mutagenesis analyses of CopC-mediated ADPR deacylization in vitro and animal infection in vivo. Our study offers a structural framework for understanding the molecular basis of arginine ADPR deacylization catalyzed by the CopC family. Structural insights into caspase ADPR deacylization catalyzed by a bacterial effector and host calmodulin.,Zhang K, Peng T, Tao X, Tian M, Li Y, Wang Z, Ma S, Hu S, Pan X, Xue J, Luo J, Wu Q, Fu Y, Li S Mol Cell. 2022 Dec 15;82(24):4712-4726.e7. doi: 10.1016/j.molcel.2022.10.032. , Epub 2022 Nov 23. PMID:36423631[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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