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Identification of Protein Interacting Partners Using Tandem Affinity Purification
Published on: February 25, 2012
Potyvirus terminal protein VPg, effector of host eukaryotic initiation factor eIF4E
R Grzela1, L Strokovska, J-P Andrieu
1Institute of Biochemistry and Biophysics (IBB), Polish Academy of Sciences, Warsaw, Poland.
Biochimie
|April 22, 2006
Summary
Potato virus Y
Area of Science:
- Virology
- Molecular Biology
- Biochemistry
Background:
- Potyvirus RNA features a virus-encoded protein (VPg) essential for infectivity.
- VPg's function is linked to its interaction with eukaryotic translation initiation factor 4E (eIF4E), a cap-binding protein.
Purpose of the Study:
- To characterize the binding affinity between potato virus Y's VPg and plant eIF4Es.
- To map the binding site of eIF(iso)4E on VPg.
- To elucidate the mechanism by which VPg inhibits host protein synthesis.
Main Methods:
- Characterization of dissociation constants for VPg/eIF4E interactions.
- Mapping of the eIF(iso)4E attachment region on VPg.
- Analysis of cell-free protein synthesis inhibition.
Main Results:
- VPg binds to plant eIF4Es and their isoforms with specific affinities.
- VPg interaction with eIF4E inhibits cell-free protein synthesis by displacing the cap moiety.
- VPg induces structural changes in eIF4E, reducing its cap-binding affinity.
- eIF(iso)4G enhances the interaction between VPg and eIF(iso)4E.
Conclusions:
- VPg acts as a novel eIF4E-binding protein.
- VPg inhibits host protein synthesis by preventing cap attachment to eIF4E early in initiation complex formation.
- The findings reveal a conserved mechanism of cap and VPg interaction with eIF4E.
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