2Institute of Protein Research, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
3Institute of Problems of Chemical Physics, Russian Academy of Sciences, 142432 Chernogolovka, Moscow Region, Russia
4Scientific and Educational Center in Chernogolovka, Moscow Region State University, 141014 Mytishchi, Moscow Region, Russia
5Faculty of Fundamental Physical and Chemical Engineering, Lomonosov Moscow State University, 119991 Moscow, Russia
* To whom correspondence should be addressed.
Received May 18, 2021; Revised May 30, 2021; Accepted May 31, 2021
Potato virus Y (PVY) is one of the most common and harmful plant viruses. Translation of viral RNA starts with the interaction between the plant cap-binding translation initiation factors eIF4E and viral genome-linked protein (VPg) covalently attached to the viral RNA. Disruption of this interaction is one of the natural mechanisms of plant resistance to PVY. The multigene eIF4E family in the potato (Solanum tuberosum L.) genome contains genes for the translation initiation factors eIF4E1, eIF4E2, and eIF(iso)4E. However, which of these factors can be recruited by the PVY, as well as the mechanism of this interaction, remain obscure. Here, we showed that the most common VPg variant from the PVY strain NTN interacts with eIF4E1 and eIF4E2, but not with eIF(iso)4E. Based on the VPg, eIF4E1, and eIF4E2 models and data on the natural polymorphism of VPg amino acid sequence, we suggested that the key role in the recognition of potato cap-binding factors belongs to the R104 residue of VPg. To verify this hypothesis, we created VPg mutants with substitutions at position 104 and examined their ability to interact with potato eIF4E factors. The obtained data were used to build the theoretical model of the VPg-eIF4E2 complex that differs significantly from the earlier models of VPg complexes with eIF4E proteins, but is in a good agreement with the current biochemical data.
KEY WORDS: eIF4E, potato virus Y, VPg, translation initiation