Virulence factor of potato virus Y, genome-attached terminal protein VPg, is a highly disordered protein.
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.
Grzela
Renata
R
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.
Szolajska
Ewa
E
Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
Ebel
Christine
C
Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France.
Madern
Dominique
D
Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France.
Favier
Adrien
A
Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France.
Wojtal
Izabela
I
Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
Zagorski
Wlodzimierz
W
Institute of Biochemistry and Biophysics of Polish Academy of Sciences, 02106 Warszawa, Poland.
Chroboczek
Jadwiga
J
Institut de Biologie Structurale JP Ebel, 41 rue Jules Horowitz, CEA, CNRS, F-38027 Grenoble, France. Electronic address: wisia@ibs.fr.
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*
D014764:Viral Proteins; D037521:Virulence Factors