Spectroscopic Investigation of the Kinetic Mechanism Involved in the Association of Potyviral VPg with the Host Plant Translation Initiation Factor eIF4E

• Published in: International journal of molecular sciences 2020-08, Vol.21 (16), p.5618
• Main Authors: Walter, Jocelyne, Barra, Amandine, Charon, Justine, Tavert-Roudet, Geneviève, Michon, Thierry
• Format: Article
• Language: English
• Subjects: Acid resistance; Amino Acid Sequence - genetics; Amino acids; Binding; Binding sites; Binding Sites - genetics; Complex formation; Cultivars; Disease resistance; eIF4E; Energy transfer; Eukaryotic Initiation Factor-4E - chemistry; Eukaryotic Initiation Factor-4E - genetics; Fluorescence; Fluorescence spectroscopy; Genome, Viral - genetics; Genomes; Host plants; Host-Pathogen Interactions - genetics; induced folding; Initiation factor eIF-4E; intrinsically disordered protein; Kinetics; Lettuce; Life Sciences; Mutation; Peptides; Phytopathology and phytopharmacy; Plant Defense Against Herbivory - genetics; Plant Diseases - genetics; Plant Diseases - virology; Plant Proteins - chemistry; Plant Proteins - genetics; potyvirus; Potyvirus - chemistry; Potyvirus - genetics; Potyvirus - pathogenicity; Protein Binding - genetics; Proteins; protein–protein interaction; Synthetic peptides; Vegetal Biology; Viral Proteins - chemistry; Viral Proteins - genetics; Viruses; VPg
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21165618

The infectious cycle of potyviruses requires the formation of a complex between the viral genome-linked protein VPg and the host eukaryotic translation initiation factor 4E, eIF4E. Mutations associated with plant resistance to potyviruses were previously mapped at the eIF4E surface, while on the virus side, mutations leading to plant resistance breaking were identified within the VPg. In the present study, fluorescence spectroscopy was used to probe the contribution of the VPg intrinsically disordered region bearing amino acids determinant of the resistance breaking, to the VPg-eIF4E binding mechanism. Synthetic peptides encompassing the VPg central region were found to tightly bind to eIF4E. Fluorescence energy transfer experiments show that, upon binding to eIF4E, the N and C termini of the VPg fragment move closer to one another, at a distance compatible with a α-helix folding. When the VPg region, which contains amino acids associated with resistance breakdown, is appended to VPg , the complex formation with eIF4E switches from a single-step to a two-step kinetic model. This study revisits a recent investigation of the VPg-eIF4E complex by specifying the contribution of the VPg central helix and its appended disordered region to VPg association with eIF4E.