title: Virulence factor of potato virus Y, genome-attached terminal protein VPg, is a highly disordered protein.
abstract: Potato virus Y (PVY) is a common potyvirus of agricultural importance, belonging to the picornavirus superfamily of RNA plus-stranded viruses. A covalently linked virus-encoded protein VPg required for virus infectivity is situated at the 5' end of potyvirus RNA. VPg seems to be involved in multiple interactions, both with other viral products and host proteins. VPgs of potyviruses have no known homologs, and there is no atomic structure available. To understand the molecular basis of VPg multifunctionality, we have analyzed structural features of VPg from PVY using structure prediction programs, functional assays, and biochemical and biophysical analyses. Structure predictions suggest that VPg exists in a natively unfolded conformation. In contrast with ordered proteins, PVY VPg is not denatured by elevated temperatures, has sedimentation values incompatible with a compact globular form, and shows a CD spectrum of a highly disordered protein, and HET-HETSOFAST NMR analysis suggests the presence of large unstructured regions. Although VPg has a propensity to form dimers, no functional differences were seen between the monomer and dimer. These data strongly suggest that the VPg of PVY should be classified among intrinsically disordered proteins. Intrinsic disorder lies at the basis of VPg multifunctionality, which is necessary for virus survival in the host.
authors.affiliation: Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France; Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
authors.forename: Renata
authors.initials: R
authors.lastname: Grzela
authors.affiliation: Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Szolajska
authors.affiliation: Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Ebel
authors.affiliation: Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Madern
authors.affiliation: Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France.
authors.forename: Adrien
authors.initials: A
authors.lastname: Favier
authors.affiliation: Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
authors.forename: Izabela
authors.initials: I
authors.lastname: Wojtal
authors.affiliation: Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
authors.forename: Wlodzimierz
authors.initials: W
authors.lastname: Zagorski
authors.affiliation: Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France. Electronic address: wisia@ibs.fr.
authors.forename: Jadwiga
authors.initials: J
authors.lastname: Chroboczek
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D019281:Dimerization; D004591:Electrophoresis, Polyacrylamide Gel; D016679:Genome, Viral; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017800:Potyvirus / Q000235:genetics / Q000378:metabolism*; D013696:Temperature; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D037521:Virulence Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D014764:Viral Proteins; D037521:Virulence Factors