SDS-PAGE analysis. (a) HCV3a E2 protein expression in inclusion bodies. Lane 1, Uninduced E2 total cell lysate; Lane 2, Induced E2 total cell lysate; Lane 3, Uninduced E2 supernatant; Lane 4, Induced E2 supernatant; Lane 5, Uninduced E2 pellet; Lane 6, Induced E2 pellet. (b) Partial protein purification of HCV3a envelope glycoprotein E2 after fractional dialysis with urea. Lane 1, E2 protein expression; Lanes 2-7, Fractional dialysis with 6M, 4M, 3M, 2M, 1M and 0M urea, respectively. (c) HCV3a E2 purified protein at 39 kDa; Lane 1, E2 purified protein; Lane M, BenchMarkTM Protein ladder (Novex Cat # 10747-102).