Specificity of binding to four-way junctions in DNA by bacteriophage T7 endonuclease I

作者：Carol A. Parsons, Stephen Craig West · 发表于：Nucleic Acids Research · 年份：1990 · DOI：10.1093/nar/18.15.4377 · 被引用次数：38 · 研究领域：DNA and Nucleic Acid Chemistry、Advanced biosensing and bioanalysis techniques、DNA Repair Mechanisms

T7 endonuclease I binds specifically to four-way junctions in duplex DNA and promotes their resolution into linear duplexes. Under conditions in which the nuclease activity is blocked by the absence of divalent cations, the enzyme forms a distinct protein-DNA complex with the junction, as detected by gel retardation and filter binding assays. The formation of this complex is structure-specific and contrasts with the short-lived binding complexes formed on linear duplex DNA. The binding complex between T7 endonuclease I and a synthetic Holliday junction analog has been probed with hydroxyl radicals. The results indicate that the nuclease binds all four strands about the junction point.