Molecular modeling and docking study of FV fragment of monoclonal antibody generated agaisnt C-terminal fragment of merozoite surface protein-1 from Plasmodium vivax

Background: Plasmodium vivax is the second most important malaria parasites for human. During merozoite invasion, only MSP-119 enters the red blood cell because it remains attached with the surface of the parasite. MSP-119 isa leading vaccine candidate. In this study, murine monoclonal antibody was raised against c-terminal fragment of merozoite surface protein-1 from plasmodium vivaxand molecular characterized. Homology modeling of the variable region (Fv) of monoclonal antibodyand its docking with MSP-119was performed. Discontinue epitope was also predict through docking. Materials and Methods: Murine MAb was raised against the antigens of P. vivax produced during erythrocytic stage. MSP-119 was identified using western blotting and immunoprecipitation. cDNA was synthesised from the total RNA of hybridoma cell line. Fv region of MAb 9CL was amplified from the cDNA. The resultant amplicons were cloned and sequenced. Homology modelling of the obtained Fv sequence was done by PIGS web server. Docking analysis of the selected template i.e. 2NPR was done by Cluspro : protein-protein docking server. Result: MAb 9CL has shown positive response against P. vivax antigens. A 14-17 kDa protein band was observed in western blot and on immunoprecipitation. The band was identified as MSP119. Best homology model was selected for the docking study. Docking analysis shows that 10 residues of 2NPR (discontinue epitope) makes direct contact with the combining site of 9CL. The results also reveal that 20 H-bonds are formed between 9CL-2NPR complex. Conclusion: Discontinue epitope prediction will facilitate designing of a short peptide for peptide based vaccine, which can be effectively used as a diagnostic assay for malaria.