title: Isolation and characterization of the DNA and protein binding activities of adenovirus core protein V.
abstract: The structure of adenovirus outer capsid was revealed recently at 3- to 4-Å resolution (V. Reddy, S. Natchiar, P. Stewart, and G. Nemerow, Science 329:1071-1075, 2010, http://dx.doi.org/10.1126/science.1187292); however, precise details on the function and biochemical and structural features for the inner core still are lacking. Protein V is one the most important components of the adenovirus core, as it links the outer capsid via association with protein VI with the inner DNA core. Protein V is a highly basic protein that strongly binds to DNA in a nonspecific manner. We report the expression of a soluble protein V that exists in monomer-dimer equilibrium. Using reversible cross-linking affinity purification in combination with mass spectrometry, we found that protein V contains multiple DNA binding sites. The binding sites from protein V mediate heat-stable nucleic acid associations, with some of the binding sites possibly masked in the virus by other core proteins. We also demonstrate direct interaction between soluble proteins V and VI, thereby revealing the bridging of the inner DNA core with the outer capsid proteins. These findings are consistent with a model of nucleosome-like structures proposed for the adenovirus core and encapsidated DNA. They also suggest an additional role for protein V in linking the inner nucleic acid core with protein VI on the inner capsid shell.
  
  
  OBJECTIVE
  Scant knowledge exists of how the inner core of adenovirus containing its double-stranded DNA (dsDNA) genome and associated proteins is organized. Here, we report a purification scheme for a recombinant form of protein V that allowed analysis of its interactions with the nucleic acid core region. We demonstrate that protein V exhibits stable associations with dsDNA due to the presence of multiple nucleic acid binding sites identified both in the isolated recombinant protein and in virus particles. As protein V also binds to the membrane lytic protein VI molecules, this core protein may serve as a bridge from the inner dsDNA core to the inner capsid shell.
authors.affiliation: Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Jimena
authors.initials: J
authors.lastname: Pérez-Vargas
authors.affiliation: Department of Molecular & Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Vaughan
authors.affiliation: Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Carolyn
authors.initials: C
authors.lastname: Houser
authors.affiliation: Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Kathryn M
authors.initials: KM
authors.lastname: Hastie
authors.affiliation: Department of Molecular & Cellular Biochemistry, Indiana University, Bloomington, Indiana, USA.
authors.forename: C Cheng
authors.initials: CC
authors.lastname: Kao
authors.affiliation: Department of Immunology and Microbial Sciences, The Scripps Research Institute, La Jolla, California, USA gnemerow@scripps.edu.
authors.forename: Glen R
authors.initials: GR
authors.lastname: Nemerow
mesh_terms: D000256:Adenoviridae / Q000235:genetics* / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D002213:Capsid / Q000378:metabolism; D036022:Capsid Proteins / Q000235:genetics / Q000378:metabolism; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014758:Viral Core Proteins / Q000235:genetics* / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism*; D014771:Virion / Q000235:genetics / Q000378:metabolism
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; D011994:Recombinant Proteins; D014758:Viral Core Proteins; D014764:Viral Proteins