Generation and molecular docking analysis of specific single-chain variable fragments selected by phage display against the recombinant nucleocapsid protein of fig mosaic virus

摘要

The mosaic disease caused by fig mosaic virus (FMV) is considered the plague of fig worldwide. A naive phage display library, raised against the recombinant nucleocapsid protein of FMV (FMV-Np) was screened to obtain specific monoclonal recombinant antibodies in the form of single chain variable fragments (scFvs). After three rounds of biopanning, the bacterially expressed FMV-Np was used as an antigen for selecting specific phages for the production of specific soluble scFvs to be used in immunological assays. The binding specificity of scFvs against FMV-infected fig samples was evaluated by immunoblotting and Plate trapped antigen-ELISA (PTA-ELISA), which revealed efficient of the resultant scFvs to the target antigen. Silico homology-modelling and molecular docking analysis confirmed the scFv and FMV-Np interactions with the anti-FMV-Np scFv through an estimated binding energy of -650 kj mol(-1) considered to be generated from the interactions between 13 amino acids residues predicted as putative epitopes in the interface pocket of FMV-Np and scFv antibody. This high affinity was further confirmed in the specificity of ELISA and immunoblotting assays. This is the first report on the application of phage display technology to generate specific recombinant scFvs against FMV that can be applied in development of antibody-mediated protection strategy to control the fig mosaic disease.