Human RECQ1 helicase-driven DNA unwinding, annealing, and branch migration: Insights from DNA complex structures

DOI: 10.1073/pnas.1417594112
PMID: 25831490

Authors: Ashley Pike (University of Oxford) , Shivasankari Gomathinayagam (Saint Louis University School of Medicine) , Paolo Swuec (Cancer Research UK Clare Hall Laboratories) , Matteo Berti (Saint Louis University School of Medicine) , Ying Zhang (University of Oxford) , Christina Schnecke (University of Oxford) , Francesca Marino (Sincrotrone Trieste) , Frank Von Delft (University of Oxford) , Ludovic Renault (Cancer Research UK Clare Hall Laboratories) , Alessandro Costa (Cancer Research UK Clare Hall Laboratories) , Opher Gileadi (University of Oxford) , Alessandro Vindigni (Saint Louis University School of Medicine)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Proceedings Of The National Academy Of Sciences , VOL 112 (14) , PAGES 4286 - 4291

State: Published (Approved)
Published: April 2015
Diamond Proposal Number(s): 442

Abstract: RecQ helicases are a widely conserved family of ATP-dependent motors with diverse roles in nearly every aspect of bacterial and eukaryotic genome maintenance. However, the physical mechanisms by which RecQ helicases recognize and process specific DNA replication and repair intermediates are largely unknown. Here, we solved crystal structures of the human RECQ1 helicase in complexes with tailed-duplex DNA and ssDNA. The structures map the interactions of the ssDNA tail and the branch point along the helicase and Zn-binding domains, which, together with reported structures of other helicases, define the catalytic stages of helicase action. We also identify a strand-separating pin, which (uniquely in RECQ1) is buttressed by the protein dimer interface. A duplex DNA-binding surface on the C-terminal domain is shown to play a role in DNA unwinding, strand annealing, and Holliday junction (HJ) branch migration. We have combined EM and analytical ultracentrifugation approaches to show that RECQ1 can form what appears to be a flat, homotetrameric complex and propose that RECQ1 tetramers are involved in HJ recognition. This tetrameric arrangement suggests a platform for coordinated activity at the advancing and receding duplexes of an HJ during branch migration.

Diamond Keywords: Enzymes

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: I04-Macromolecular Crystallography

Added On: 24/04/2015 09:26

Documents:
4286.full.pdf

Discipline Tags:

Biochemistry Chemistry Structural biology Life Sciences & Biotech

Technical Tags:

Diffraction Macromolecular Crystallography (MX)