title: The structure of the NTPase that powers DNA packaging into Sulfolobus turreted icosahedral virus 2.
abstract: Biochemical reactions powered by ATP hydrolysis are fundamental for the movement of molecules and cellular structures. One such reaction is the encapsidation of the double-stranded DNA (dsDNA) genome of an icosahedrally symmetric virus into a preformed procapsid with the help of a genome-translocating NTPase. Such NTPases have been characterized in detail from both RNA and tailed DNA viruses. We present four crystal structures and the biochemical activity of a thermophilic NTPase, B204, from the nontailed, membrane-containing, hyperthermoacidophilic archaeal dsDNA virus Sulfolobus turreted icosahedral virus 2. These are the first structures of a genome-packaging NTPase from a nontailed, dsDNA virus with an archaeal host. The four structures highlight the catalytic cycle of B204, pinpointing the molecular movement between substrate-bound (open) and empty (closed) active sites. The protein is shown to bind both single-stranded and double-stranded nucleic acids and to have an optimum activity at 80°C and pH 4.5. The overall fold of B204 places it in the FtsK-HerA superfamily of P-loop ATPases, whose cellular and viral members have been suggested to share a DNA-translocating mechanism.
authors.affiliation: Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
authors.forename: Lotta J
authors.initials: LJ
authors.lastname: Happonen
authors.forename: Esko
authors.initials: E
authors.lastname: Oksanen
authors.forename: Lassi
authors.initials: L
authors.lastname: Liljeroos
authors.forename: Adrian
authors.initials: A
authors.lastname: Goldman
authors.forename: Tommi
authors.initials: T
authors.lastname: Kajander
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Butcher
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D023641:Archaeal Viruses / Q000201:enzymology* / Q000502:physiology*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D042003:DNA Packaging; D004279:DNA, Viral / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008958:Models, Molecular; D043583:Nucleoside-Triphosphatase / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D016944:Sulfolobus / Q000821:virology*; D013696:Temperature
chemical_list: D004279:DNA, Viral; D000255:Adenosine Triphosphate; D043583:Nucleoside-Triphosphatase