TRUNCATING THE PUTATIVE MEMBRANE ASSOCIATION REGION CIRCUMVENTS THE DIFFICULTY OF EXPRESSING HEPATITIS-C VIRUS PROTEIN E1 IN ESCHERICHIA-COLI

The putative El of hepatitis C virus (HCV) was expressed in Escherichi a coli using a glutathione-S-transferase (GST) fusion protein system. The full length El protein is difficult to express. A series of El DNA fragments was generated and used for expression vector construction. Fusion proteins containing the El C-terminal region could not be expre ssed. When this region was truncated, the fusion proteins were synthes ized to high levels. The possibility of this C-terminal region hamperi ng the production of fusion protein tvas further explored. A construct with this segment directly fused to the C-terminus of GST indeed gene rated no detectable recombinant protein. According to the predicted st ructure of El, this region may have membrane-associating properties. T he expression results suggest a general approach to facilitate the pro duction of viral membrane proteins in prokaryotes. Furthermore, these recombinant El proteins generated as antigens were used for Western bl otting with sera from HCV-infected individuals. It was found that El i s antigenic during HCV natural infection.