Efficient cleavage by signal peptide peptidase requires residues within the signal peptide between the core and E1 proteins of hepatitis C virus strain J1

Maturation of hepatitis C virus (HCV) core protein requires cleavage by signal peptidase (SP) and signal peptide peptidase (SPP) at a signal peptide between core and the E1 glycoprotein. For HCV strain Glasgow, amino acids Ala(180), Ser(183) and Cys(184) within the signal peptide have previously been shown to be essential for efficient SPP cleavage. By contrast, these residues apparently did not contribute to core maturation in HCV strain J1. In the present study, the source of this discrepancy has been analysed and it is concluded that interpretation of the strain J1 data was incorrect, due to the inability to separate wild-type and mutant forms of core on gels by using standard buffer systems.