1. Mechanistic insights into Lhr helicase function in DNA repair
- Author
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Christopher D.O. Cooper, Ryan J. Buckley, Kevin Kramm, Edward L. Bolt, and Dina Grohmann
- Subjects
DNA Replication ,Methanobacteriaceae ,DNA Repair ,DNA repair ,Protein Conformation ,Archaeal Proteins ,DNA, Single-Stranded ,Lhr ,Biochemistry ,Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,Holliday junction ,Directionality ,A-DNA ,Molecular Biology ,DNA, Chromosomes & Chromosomal Structure ,Research Articles ,030304 developmental biology ,0303 health sciences ,biology ,Chemistry ,030302 biochemistry & molecular biology ,DNA replication ,DNA Helicases ,Helicase ,Cell Biology ,DNA Replication Fork ,Cell biology ,helicase ,DNA, Archaeal ,biology.protein ,DNA - Abstract
The DNA helicase Large helicase-related (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 with 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.
- Published
- 2020