Loop extrusion-mediated plasmid DNA cleavage by the bacterial SMC Wadjet complex.

ABSTRACT: Structural maintenance of chromosomes (SMC) protein complexes play pivotal roles in genome organization and maintenance across all domains of life. In prokaryotes, SMC family Wadjet complexes structurally resemble the widespread MukBEF genome-organizing complexes but serve a defensive role by inhibiting plasmid transformation. We previously showed that Wadjet specifically cleaves circular DNA; however, the molecular mechanism underlying DNA substrate recognition remains unclear. Here, we use in vitro single-molecule imaging to directly visualize DNA loop extrusion and plasmid cleavage by Wadjet. We find that Wadjet is a symmetric DNA loop extruder that simultaneously reels in DNA from both sides of a growing loop and that this activity requires a dimeric JetABC supercomplex containi

SUBMITTER: Pradhan B 

PROVIDER: S-EPMC10889018 | biostudies-literature | 2024 Feb

REPOSITORIES: biostudies-literature