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-Structure paper
タイトル | Structural basis for plasmid restriction by SMC JET nuclease. |
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ジャーナル・号・ページ | Mol Cell, Vol. 84, Issue 5, Page 883-896.e7, Year 2024 |
掲載日 | 2024年3月7日 |
著者 | Florian Roisné-Hamelin / Hon Wing Liu / Michael Taschner / Yan Li / Stephan Gruber / |
PubMed 要旨 | DNA loop-extruding SMC complexes play crucial roles in chromosome folding and DNA immunity. Prokaryotic SMC Wadjet (JET) complexes limit the spread of plasmids through DNA cleavage, yet the ...DNA loop-extruding SMC complexes play crucial roles in chromosome folding and DNA immunity. Prokaryotic SMC Wadjet (JET) complexes limit the spread of plasmids through DNA cleavage, yet the mechanisms for plasmid recognition are unresolved. We show that artificial DNA circularization renders linear DNA susceptible to JET nuclease cleavage. Unlike free DNA, JET cleaves immobilized plasmid DNA at a specific site, the plasmid-anchoring point, showing that the anchor hinders DNA extrusion but not DNA cleavage. Structures of plasmid-bound JetABC reveal two presumably stalled SMC motor units that are drastically rearranged from the resting state, together entrapping a U-shaped DNA segment, which is further converted to kinked V-shaped cleavage substrate by JetD nuclease binding. Our findings uncover mechanical bending of residual unextruded DNA as molecular signature for plasmid recognition and non-self DNA elimination. We moreover elucidate key elements of SMC loop extrusion, including the motor direction and the structure of a DNA-holding state. |
リンク | Mol Cell / PubMed:38309275 |
手法 | EM (単粒子) |
解像度 | 4.17 - 4.78 Å |
構造データ | EMDB-18201, PDB-8q72: EMDB-18208: E. coli plasmid-borne JetABCD(E248A) in a cleavage-competent state EMDB-18211: E. coli plasmid-borne JetABC in a cleavage-competent state |
化合物 | ChemComp-ADP: |
由来 |
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キーワード | DNA BINDING PROTEIN / SMC complexes / DNA loop extrusion / nuclease / bacterial immunity / defense system / topoisomerase / plamid restriction / MksBEFG / Wadjet / EptABCD / horizontal gene transfer / DNA kinking |