Expression of recombinant West Nile virus prM protein fused to an affinity tag for use as a diagnostic antigen

► West Nile virus prM was successfully expressed without E. ► Position of the His-tag on the N-terminus of prM protein was crucial for native presentation of His-tag, but disrupted prM folding. ► The V5-tag was introduced at the C-terminus for successful affinity isolation under native conditions.