title: Mechanistic insight into the interaction of BLM helicase with intra-strand G-quadruplex structures.
abstract: Bloom syndrome is an autosomal recessive disorder caused by mutations in the RecQ family helicase BLM that is associated with growth retardation and predisposition to cancer. BLM helicase has a high specificity for non-canonical G-quadruplex (G4) DNA structures, which are formed by G-rich DNA strands and play an important role in the maintenance of genomic integrity. Here we used single-molecule FRET to define the mechanism of interaction of BLM helicase with intra-stranded G4 structures. We show that the activity of BLM is substrate dependent, and highly regulated by a short-strand DNA (ssDNA) segment that separates the G4 motif from double-stranded DNA. We demonstrate cooperativity between the RQC and HRDC domains of BLM during binding and unfolding of the G4 structure, where the RQC domain interaction with G4 is stabilized by HRDC binding to ssDNA. We present a model that proposes a unique role for G4 structures in modulating the activity of DNA processing enzymes.
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, MSB 394, 550 First Avenue, New York, New York 10016, USA.
authors.forename: Sujoy
authors.initials: S
authors.lastname: Chatterjee
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, MSB 394, 550 First Avenue, New York, New York 10016, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Zagelbaum
authors.affiliation: Genome Integrity group, Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Pavel
authors.initials: P
authors.lastname: Savitsky
authors.affiliation: Institute of Molecular Cancer Research, University of Zurich, CH-8057 Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Sturzenegger
authors.affiliation: 1] NovoNordisk Foundation Center for Protein Research, University of Copenhagen, 2200 Copenhagen, Denmark [2] Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark.
authors.forename: Diana
authors.initials: D
authors.lastname: Huttner
authors.affiliation: Institute of Molecular Cancer Research, University of Zurich, CH-8057 Zurich, Switzerland.
authors.forename: Pavel
authors.initials: P
authors.lastname: Janscak
authors.affiliation: Department of Cellular and Molecular Medicine, University of Copenhagen, 2200 Copenhagen, Denmark.
authors.forename: Ian D
authors.initials: ID
authors.lastname: Hickson
authors.affiliation: Genome Integrity group, Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Opher
authors.initials: O
authors.lastname: Gileadi
authors.affiliation: Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, MSB 394, 550 First Avenue, New York, New York 10016, USA.
authors.forename: Eli
authors.initials: E
authors.lastname: Rothenberg
mesh_terms: D001816:Bloom Syndrome / Q000235:genetics; D002460:Cell Line; D004260:DNA Repair / Q000235:genetics; D004277:DNA, Single-Stranded / Q000235:genetics*; D005090:Exodeoxyribonucleases / Q000235:genetics; D031541:Fluorescence Resonance Energy Transfer; D054856:G-Quadruplexes; D006801:Humans; D008957:Models, Genetic; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases / Q000235:genetics*; D000071657:Werner Syndrome Helicase
chemical_list: D004277:DNA, Single-Stranded; D005090:Exodeoxyribonucleases; C097151:Bloom syndrome protein; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase