title: Structure-Based Mutagenesis of Sulfolobus Turreted Icosahedral Virus B204 Reveals Essential Residues in the Virion-Associated DNA-Packaging ATPase.
abstract: Sulfolobus turreted icosahedral virus (STIV), an archaeal virus that infects the hyperthermoacidophile Sulfolobus solfataricus, is one of the most well-studied viruses of the domain Archaea. STIV shares structural, morphological, and sequence similarities with viruses from other domains of life, all of which are thought to belong to the same viral lineage. Several of these common features include a conserved coat protein fold, an internal lipid membrane, and a DNA-packaging ATPase. B204 is the ATPase encoded by STIV and is thought to drive packaging of viral DNA during the replication process. Here, we report the crystal structure of B204 along with the biochemical analysis of B204 mutants chosen based on structural information and sequence conservation patterns observed among members of the same viral lineage and the larger FtsK/HerA superfamily to which B204 belongs. Both in vitro ATPase activity assays and transfection assays with mutant forms of B204 confirmed the essentiality of conserved and nonconserved positions. We also have identified two distinct particle morphologies during an STIV infection that differ in the presence or absence of the B204 protein. The biochemical and structural data presented here are not only informative for the STIV replication process but also can be useful in deciphering DNA-packaging mechanisms for other viruses belonging to this lineage.
  
  
  OBJECTIVE
  STIV is a virus that infects a host from the domain Archaea that replicates in high-temperature, acidic environments. While STIV has many unique features, there exist several striking similarities between this virus and others that replicate in different environments and infect a broad range of hosts from Bacteria and Eukarya. Aside from structural features shared by viruses from this lineage, there exists a significant level of sequence similarity between the ATPase genes carried by these different viruses; this gene encodes an enzyme thought to provide energy that drives DNA packaging into the virion during infection. The experiments described here highlight the elements of this enzyme that are essential for proper function and also provide supporting evidence that B204 is present in the mature STIV virion.
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA CSIRO Land & Water, Acton, ACT, Australia.
authors.forename: Nikki
authors.initials: N
authors.lastname: Dellas
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA.
authors.forename: Jamie C
authors.initials: JC
authors.lastname: Snyder
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Dills
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA.
authors.forename: Sheena J
authors.initials: SJ
authors.lastname: Nicolay
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA.
authors.forename: Keshia M
authors.initials: KM
authors.lastname: Kerchner
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA.
authors.forename: Susan K
authors.initials: SK
authors.lastname: Brumfield
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA.
authors.forename: C Martin
authors.initials: CM
authors.lastname: Lawrence
authors.affiliation: Thermal Biology Institute, Montana State University, Bozeman, Montana, USA Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA myoung@montana.edu.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Young
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D004252:DNA Mutational Analysis; D042003:DNA Packaging; D004267:DNA Viruses / Q000201:enzymology* / Q000502:physiology; D008958:Models, Molecular; D011487:Protein Conformation; D048229:Sulfolobus solfataricus / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D000251:Adenosine Triphosphatases