title: Regulation of a viral proteinase by a peptide and DNA in one-dimensional space: II. adenovirus proteinase is activated in an unusual one-dimensional biochemical reaction.
abstract: Late in an adenovirus infection, the viral proteinase (AVP) becomes activated to process virion precursor proteins used in virus assembly. AVP is activated by two cofactors, the viral DNA and pVIc, an 11-amino acid peptide originating from the C terminus of the precursor protein pVI. There is a conundrum in the activation of AVP in that AVP and pVI are sequence-independent DNA-binding proteins with nm equilibrium dissociation constants such that in the virus particle, they are predicted to be essentially irreversibly bound to the viral DNA. Here, we resolve that conundrum by showing that activation of AVP takes place on the one-dimensional contour of DNA. In vitro, pVI, a substrate, slides on DNA via one-dimensional diffusion, D(1) = 1.45 × 10(6) bp(2)/s, until it binds to AVP also on the same DNA molecule. AVP, partially activated by being bound to DNA, excises pVIc, which binds to the AVP molecule that cut it out. pVIc then forms a disulfide bond with AVP forming the fully active AVP-pVIc complex bound to DNA. In vivo, in heat-disrupted immature virus, AVP was also activated by pVI in DNA-dependent reactions. This activation mechanism illustrates a new paradigm for virion maturation and a new way, by sliding on DNA, for bimolecular complexes to form among proteins not involved in DNA metabolism.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Vito
authors.initials: V
authors.lastname: Graziano
authors.forename: Guobin
authors.initials: G
authors.lastname: Luo
authors.forename: Paul C
authors.initials: PC
authors.lastname: Blainey
authors.forename: Ana J
authors.initials: AJ
authors.lastname: Pérez-Berná
authors.forename: William J
authors.initials: WJ
authors.lastname: McGrath
authors.forename: S Jane
authors.initials: SJ
authors.lastname: Flint
authors.forename: Carmen
authors.initials: C
authors.lastname: San Martín
authors.forename: X Sunney
authors.initials: XS
authors.lastname: Xie
authors.forename: Walter F
authors.initials: WF
authors.lastname: Mangel
mesh_terms: D000260:Adenoviruses, Human / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003546:Cysteine Endopeptidases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism*; D004220:Disulfides / Q000737:chemistry / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D011485:Protein Binding; D011498:Protein Precursors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics; D014771:Virion / Q000201:enzymology* / Q000235:genetics
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; D004220:Disulfides; D011498:Protein Precursors; D011994:Recombinant Proteins; C090876:polypeptide VI, adenovirus; D003546:Cysteine Endopeptidases; C091827:adenain