Expression of structural proteins encoded by the 5′ terminus of HCV RNA, HCV core aa 1–173 (lanes 4–6) and F-protein (lanes 7–9). E. coli were transformed with plasmids expressing core 1–173 and F-protein; cell lysates were resolved by 15% SDS-PAGE; gel was stained with Coomassie brilliant blue. HCV core 1–173 (0.5, 1, and 2.5 µg per well, lanes 4–6) and F-protein (0.5, 1, and 2.5 µg per well, lanes 7–9), respectively. Controls: His-tagged outer surface protein BB0689 of B. burgdorferi (2.5 µg, lane 1), lysozyme (2.5 µg, lane 2); HBcAg (2.5 µg, lane 3); PageRuler Plus Prestained Protein Ladder (Thermo Scientific, lane M). Position of molecular mass markers is given on the left.