HCV-1a NS3 protease/helicase immunodominant region Protein (GST)

HCV NS3 displays three enzymatic activities: serine protease, NTPase, and RNA helicase. HCV NS3 serine protease, in association with NS4A, is responsible for the cleavages of NS3-NS4A, NS4A-NS4B, NS4B-NS5A, and NS5A-NS5B. HCV NS3 RNA helicase binds to RNA and unwinds dsRNA in the 3' to 5' direction, and likely RNA stable secondary structure in the template strand (By similarity) . Cleaves and inhibits the host antiviral protein MAVS. NS3/NS4A complex also prevents phosphorylation of human IRF3, thus preventing the establishment of dsRNA induced antiviral state. One of the HCV proteases, NS3-4A serine protease, is a non-covalent heterodimer consisting of a catalytic subunit (the N-terminal one-third of NS3 protein) and an activating cofactor (NS4A protein) and is responsible for cleavage at four sites of the HCV polyprotein.