In silico structural analysis of Hantaan virus glycoprotein G2 and conserved epitope prediction for vaccine development

摘要

Hantaan virus (HNTV), a prototypic member of Hantavirus genus, is an etiological agent of potentially fatal hemorrhagic fever with renal syndrome (HFRS). The virus infects a large number of patients annually, with a mortality rate more than 10%. However, no treatment option or vaccine is available against the virus. The virus expresses two envelope proteins having role in viral attachment to host. Among them HNTV glycoprotein G2 has higher antigenicity making it a better target for vaccine development. However, 3-D structure of the protein is not available which is important for identifying epitopes that are essential for vaccine design. Therefore, this study was designed to predict a structural model of glycoprotein G2 and to predict peptide sequences for vaccine development containing conserved epitopes within the structure. Many of the physio-chemical and structural properties including secondary structure and di-sulfide linkage of the protein were predicted using a number of computational tools. The 3D structure of the protein was modeled using I-TASSER online tool. The quality of the predicted models was evaluated with Ramachandran plot and Z-score. The structural and sequence information was used to predict B-cell and T-cell epitopes on glycoprotein G2. A model with reliable quality was generated. Using various bio-informatics and immuno-informatics tools, a total of 9 continuous B-cell and 22 T-cell epitopes were predicted having significant antigenicity. These antigenic epitopes were further analyzed for conservation and a total of 4 B-cells and 8 T-cell epitopes were found to be highly conserved in sequences from diverse origins. These epitopes revealed by the current study are recognized by immune system to protect host from HNTV infection can be potential targets for vaccine development.