title: A conserved G4 DNA binding domain in RecQ family helicases.
abstract: RecQ family helicases play important roles at G-rich domains of the genome, including the telomeres, rDNA, and immunoglobulin switch regions. This appears to reflect the unusual ability of enzymes in this family to unwind G4 DNA. How RecQ family helicases recognize this substrate has not been established. Here, we show that G4 DNA is a preferred target for BLM helicase within the context of long DNA molecules. We identify the RQC domain, found only in RecQ family enzymes, as an independent, high affinity and conserved G4 DNA binding domain; and show that binding to Holliday junctions involves both the RQC and the HRDC domains. These results provide mechanistic understanding of differences and redundancies of function and activities among RecQ family helicases, and of how deficiencies in human members of this family may contribute to genomic instability and disease.
authors.affiliation: Department of Biochemistry, University of Washington Medical School, Seattle, WA 98195, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Huber
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Duquette
authors.forename: Jerome C
authors.initials: JC
authors.lastname: Shiels
authors.forename: Nancy
authors.initials: N
authors.lastname: Maizels
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D017124:Conserved Sequence; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004265:DNA Helicases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D007700:Kinetics; D008854:Microscopy, Electron; D017434:Protein Structure, Tertiary; D053484:RecQ Helicases; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D029968:Escherichia coli Proteins; D011994:Recombinant Proteins; D004247:DNA; D000251:Adenosine Triphosphatases; C097151:Bloom syndrome protein; C506725:RECQL protein, human; C506724:RecQ protein, E coli; D004265:DNA Helicases; D053484:RecQ Helicases