Mechanistic insights into Lhr helicase function in DNA repair

Buckley, Ryan; Kramm, Kevin; Cooper, Christopher D. O.; Grohmann, Dina; Bolt, Edward L

Abstract

The DNA helicase Lhr is present throughout archaea, including in the Asgard and Nanoarchaea, and has homologues in bacteria and eukaryotes. It is thought to function in DNA repair but in a context that is not known. Our data show that archaeal Lhr preferentially targets DNA replication fork structures. In a genetic assay, expression of archaeal Lhr gave a phenotype identical to the replication-coupled DNA repair enzymes Hel308 and RecQ. Purified archaeal Lhr preferentially unwound model forked DNA substrates compared to DNA duplexes, flaps and Holliday junctions, and unwound them with directionality. Single-molecule FRET measurements showed that binding of Lhr to a DNA fork causes ATP-independent distortion and base-pair melting at, or close to, the fork branchpoint. ATP-dependent directional translocation of Lhr resulted in fork DNA unwinding through the ‘parental’ DNA strands. Interaction of Lhr with replication forks in vivo and in vitro suggests that it contributes to DNA repair at stalled or broken DNA replication.

Citation

Buckley, R., Kramm, K., Cooper, C. D. O., Grohmann, D., & Bolt, E. L. (2020). Mechanistic insights into Lhr helicase function in DNA repair. Biochemical Journal, 477(16), 2935–2947. https://doi.org/10.1042/bcj20200379

• Journal Article Type: Article
• Acceptance Date: Jul 23, 2020
• Online Publication Date: Aug 19, 2020
• Publication Date: Aug 19, 2020
• Deposit Date: Jul 29, 2020
• Publicly Available Date: Aug 20, 2021
• Journal: Biochemical Journal
• Print ISSN: 0264-6021
• Electronic ISSN: 1470-8728
• Publisher: Portland Press
• Peer Reviewed: Peer Reviewed
• Volume: 477
• Issue: 16
• Pages: 2935–2947
• DOI: https://doi.org/10.1042/bcj20200379
• Keywords: Cell Biology; Biochemistry; Molecular Biology
• Public URL: https://nottingham-repository.worktribe.com/output/4795518
• Publisher URL: https://portlandpress.com/biochemj/article/477/16/2935/225885/Mechanistic-insights-into-Lhr-helicase-function-in