Type III CRISPR-Cas complexes act as protein-assisted ribozymes during target RNA cleavage.

ABSTRACT: CRISPR-Cas systems are an adaptive immune system in bacteria and archaea that utilize CRISPR RNA-guided surveillance complexes to target complementary RNA or DNA for destruction^1-5. Target RNA cleavage at regular intervals is characteristic of type III effector complexes; however, the mechanism has remained enigmatic^6,7. Here, we determine the structures of the Synechocystis type III-Dv complex, an evolutionary intermediate in type III effectors^8,9, in pre- and post-cleavage states, which show metal ion coordination in the active sites. Using structural, biochemical, and quantum/classical molecular dynamics simulation, we reveal the structure and dynamics of the three catalytic sites, where a 2'-OH of the ribose on the target RNA acts as a nucleophil

SUBMITTER: Schwartz EA 

PROVIDER: S-EPMC10168453 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature