West Nile (WNV) is an arthropod-borne virus (arborirus) in the genus Flavivirus and the family Flaviviridae. The Flavivirus genus includes other important human pathogens such as yellow fever (YFV), Dengue vius (DENV), Zika, Japanese encephalitis (JEV), and tick borne encephalitis (TBEV). Flaviviruses are enveloped viruses with a single stranded, ?11 kb, positive-sense RNA genome, which encodes a single long open reading frame (ORF). This single ORF encodes a polyprotein that is cleaved into three structure proteins: the Capsid (C), premembrane/membrane (prM), and envelope (E) and seven non-structure protein ( NS1-NS2A-NS2B-NS3-NS4A-2K-NS4B and NS5). The virus enters the host cell by receptor mediated endocytosis. Upon internalization and acidification of the endosome, fusion of viral and vesicular membranes allows release of the genomic RNA into the cytoplasm, which serves as mRNA. Translation of the single ORF at the rough ER produces a large polyprotein that is cleaved co- and posttranslationally into the mature proteins.

Full-length West Nile virus Capsid gene ( 103aa ) encoding gene was constructed with codon optimization and expressed with a small T7-His-TEV cleavage site Tag (29aa) fusion at its N-terminal. This protein is expressed in E.coli as inclusion bodies. The final product was refolded using our unique “temperature shift inclusion body refolding” technology and chromatographically purified.