title: An archaeal Holliday junction resolving enzyme from Sulfolobus solfataricus exhibits unique properties.
abstract: The rearrangement and repair of DNA by homologous recombination often involves the creation of Holliday junctions, which must be cleaved by junction-specific endonucleases to yield recombinant duplex DNA products. Holliday junction resolving enzymes are a ubiquitous class of proteins with diverse structural and mechanistic characteristics. We have characterised an endonuclease (Hje) from the thermophilic crenarchaeote Sulfolobus solfataricus that exhibits a high degree of specificity for Holliday junctions via an apparently novel mechanism. Hje resolves four-way DNA junctions by the introduction of paired nicks in a reaction that is independent of the local nucleotide sequence, but is restricted solely to strands that are continuous in the stacked-X form of the junction. Three-way DNA junctions are cleaved only when the presence of a bulge in one strand allows the junction to stack in an analogous manner to four-way junctions. These properties differentiate Hje from all other known junction resolving enzymes.
authors.affiliation: Department of Biochemistry, MSI/WTB Complex, University of Dundee, Dundee, DD1 5EH, UK.
authors.forename: M
authors.initials: M
authors.lastname: Kvaratskhelia
authors.forename: M F
authors.initials: MF
authors.lastname: White
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D004260:DNA Repair; D019641:DNA, Archaeal / Q000378:metabolism; D004706:Endodeoxyribonucleases / Q000302:isolation & purification / Q000378:metabolism*; D045565:Holliday Junction Resolvases; D006358:Hot Temperature; D006868:Hydrolysis; D011995:Recombination, Genetic; D016944:Sulfolobus / Q000201:enzymology*
chemical_list: D017931:DNA Primers; D019641:DNA, Archaeal; D004706:Endodeoxyribonucleases; D045565:Holliday Junction Resolvases