Download MendeleyStructural mechanism of endonucleolytic processing of blocked DNA ends and hairpins by Mre11-Rad50.
Gut, F., Kashammer, L., Lammens, K., Bartho, J.D., Boggusch, A.M., van de Logt, E., Kessler, B., Hopfner, K.P.(2022) Mol Cell 82: 3513-3522.e6
- PubMed: 35987200
- DOI: https://doi.org/10.1016/j.molcel.2022.07.019
- Primary Citation of Related Structures:
7YZO, 7YZP, 7Z03 - PubMed Abstract:
DNA double-strand breaks (DSBs) threaten genome stability and are linked to tumorigenesis in humans. Repair of DSBs requires the removal of attached proteins and hairpins through a poorly understood but physiologically critical endonuclease activity by the Mre11-Rad50 complex. Here, we report cryoelectron microscopy (cryo-EM) structures of the bacterial Mre11-Rad50 homolog SbcCD bound to a protein-blocked DNA end and a DNA hairpin. The structures reveal that Mre11-Rad50 bends internal DNA for endonucleolytic cleavage and show how internal DNA, DNA ends, and hairpins are processed through a similar ATP-regulated conformational state. Furthermore, Mre11-Rad50 is loaded onto blocked DNA ends with Mre11 pointing away from the block, explaining the distinct biochemistries of 3' → 5' exonucleolytic and endonucleolytic incision through the way Mre11-Rad50 interacts with diverse DNA ends. In summary, our results unify Mre11-Rad50's enigmatic nuclease diversity within a single structural framework and reveal how blocked DNA ends and hairpins are processed.
Organizational Affiliation:
Gene Center, Ludwig-Maximilians-Universität, 81377 Munich, Germany; Department of Biochemistry, Ludwig-Maximilians-Universität, 81377 Munich, Germany.
