Leny C. Galvez | Rhosener Bhea L. Koh | Catherine Joyce B. Brillantes | Vermando M. Aquino
Abaca is an important agricultural crop in the Philippines due to the high commercial value of its fibers. The abaca industry; however, is plagued with multiple viral diseases, one of which is the banana bract mosaic virus (BBrMV). The viral protein genome-linked (VPg), one of the protein components of the BBrMV genome, is known to play significant roles in the potyviral life cycle. VPg interaction with the host eukaryotic translation initiation factor 4E (eIF4E) is required for successful potyviral infection. The study aimed to clone and characterize BBrMV VPg and determine the structural and protein-protein binding properties through in silico analysis. The full coding sequence of BBrMV VPg was isolated from BBrMV-infected abaca, expressed in E. coli, and analyzed through in silico docking analysis with predicted eIF4E proteins of abaca. SDS-PAGE analysis showed a 27 kDa protein corresponding to 6xHis-tagged BBrMV VPg which was confirmed by immunoblot analysis with anti-6xHis antibody. The protein was found both in the soluble and insoluble fractions. Homology modeling through the I-TASSER server showed BBrMV VPg had high structural similarity with the potato virus Y (PVY) VPg. Protein docking analysis between the BBrMV VPg and three putative abaca eIF4E structures via HADDOCK showed the docking of the loop α2-α3 region of BBrMV VPg to the cap-binding pocket of MteIF4E which has been previously observed for PVY VPg-eIF4E interaction. Binding affinity values and dissociation constants derived from PRODIGY analysis showed the high binding affinity between BBrMV VPg and the three abaca eIF4Es. The predicted dimeric BBrMV VPg structure showed the interface to be at the loop β4-β5 region which suggests multiple functionalities of BBrMV VPg. These findings will be significant for further elucidating the mechanism of virus-host interaction specifically in BBrMV and abaca.
ISSN 2719-1990 (Print)
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