title: Human RECQ1 helicase-driven DNA unwinding, annealing, and branch migration: insights from DNA complex structures.
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.
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom;
authors.forename: Ashley C W
authors.initials: AC
authors.lastname: Pike
authors.affiliation: Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104;
authors.forename: Shivasankari
authors.initials: S
authors.lastname: Gomathinayagam
authors.affiliation: Cancer Research UK Clare Hall Laboratories, South Mimms EN6 3LD, United Kingdom; and.
authors.forename: Paolo
authors.initials: P
authors.lastname: Swuec
authors.affiliation: Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104;
authors.forename: Matteo
authors.initials: M
authors.lastname: Berti
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom; opher.gileadi@sgc.ox.ac.uk avindign@slu.edu.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom;
authors.forename: Christina
authors.initials: C
authors.lastname: Schnecke
authors.affiliation: Structural Biology Laboratory, Sincrotrone Trieste, Trieste 34149, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Marino
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom;
authors.forename: Frank
authors.initials: F
authors.lastname: von Delft
authors.affiliation: Cancer Research UK Clare Hall Laboratories, South Mimms EN6 3LD, United Kingdom; and.
authors.forename: Ludovic
authors.initials: L
authors.lastname: Renault
authors.affiliation: Cancer Research UK Clare Hall Laboratories, South Mimms EN6 3LD, United Kingdom; and.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Costa
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom; opher.gileadi@sgc.ox.ac.uk avindign@slu.edu.
authors.forename: Opher
authors.identifier: http://orcid.org/0000-0001-6886-898X
authors.initials: O
authors.lastname: Gileadi
authors.affiliation: Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104; opher.gileadi@sgc.ox.ac.uk avindign@slu.edu.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Vindigni
mesh_terms: D000818:Animals; D002850:Chromatography, Gel; D003460:Crystallization; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry*; D004265:DNA Helicases / Q000737:chemistry*; D045566:DNA, Cruciform / Q000502:physiology; D004277:DNA, Single-Stranded / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism; D006801:Humans; D007313:Insecta; D008968:Molecular Conformation; D009691:Nucleic Acid Denaturation; D009711:Nucleotides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry
chemical_list: D045566:DNA, Cruciform; D004277:DNA, Single-Stranded; D009711:Nucleotides; D004247:DNA; C506725:RECQL protein, human; D004265:DNA Helicases; D053484:RecQ Helicases; D015032:Zinc
keywords: DNA helicases; Holliday junction; RecQ; fork reversal; genome stability
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