title: Biochemical characterization of a structure-specific resolving enzyme from Sulfolobus islandicus rod-shaped virus 2.
abstract: Sulfolobus islandicus rod shaped virus 2 (SIRV2) infects the archaeon Sulfolobus islandicus at extreme temperature (70°C-80°C) and acidity (pH 3). SIRV2 encodes a Holliday junction resolving enzyme (SIRV2 Hjr) that has been proposed as a key enzyme in SIRV2 genome replication. The molecular mechanism for SIRV2 Hjr four-way junction cleavage bias, minimal requirements for four-way junction cleavage, and substrate specificity were determined. SIRV2 Hjr cleaves four-way DNA junctions with a preference for cleavage of exchange strand pairs, in contrast to host-derived resolving enzymes, suggesting fundamental differences in substrate recognition and cleavage among closely related Sulfolobus resolving enzymes. Unlike other viral resolving enzymes, such as T4 endonuclease VII or T7 endonuclease I, that cleave branched DNA replication intermediates, SIRV2 Hjr cleavage is specific to four-way DNA junctions and inactive on other branched DNA molecules. In addition, a specific interaction was detected between SIRV2 Hjr and the SIRV2 virion body coat protein (SIRV2gp26). Based on this observation, a model is proposed linking SIRV2 Hjr genome resolution to viral particle assembly.
authors.affiliation: New England Biolabs, Inc., Ipswich, Massachusetts, United States of America. gardner@neb.com
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Gardner
authors.forename: Chudi
authors.initials: C
authors.lastname: Guan
authors.forename: William E
authors.initials: WE
authors.lastname: Jack
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D055162:Biocatalysis; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D045566:DNA, Cruciform / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D045565:Holliday Junction Resolvases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D047468:Immunoprecipitation; D058619:Maltose-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D023642:Rudiviridae / Q000201:enzymology* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D016944:Sulfolobus / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D036022:Capsid Proteins; D045566:DNA, Cruciform; D004279:DNA, Viral; D058619:Maltose-Binding Proteins; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; D045565:Holliday Junction Resolvases