Role of conserved cysteine residues in hepatitis C virus glycoprotein e2 folding and function.

Hepatitis C virus glycoprotein E2 contains 18 conserved cysteines predicted to form nine disulfide pairs. In this study, a comprehensive cysteine-alanine mutagenesis scan of all 18 cysteine residues was performed in E1E2-pseudotyped retroviruses (HCVpp) and recombinant E2 receptor-binding domain (E2 residues 384 to 661 [E2(661)]). All 18 cysteine residues were absolutely required for HCVpp entry competence.