Mechanistic insights into Lhr helicase function in DNA repair. Issue 16 (19th August 2020)

• Record Type: Journal Article
• Authors: Buckley, Ryan J.; Kramm, Kevin; Cooper, Christopher D. O.; Grohmann, Dina; Bolt, Edward L.
• Is Part Of: Biochemical journal. Volume 477:Issue 16(2020)
• Page Start: 2935
• Page End: 2947
• Publication Date: 2020-08-19
• Subjects: DNA repair -- helicase -- Lhr; Biochemistry -- Periodicals; 572
• DOI: 10.1042/BCJ20200379
• Languages: English
• ISSNs: 0264-6021

Abstract

Abstract : The DNA helicase L arge h elicase -r elated (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.