Role of Conserved Cysteine Residues in Hepatitis C Virus Glycoprotein E2 Folding and Function
| Autor: | Kathleen McCaffrey, Mark L. Edmunds, Heidi E. Drummer, Pantelis Poumbourios, Irene Boo, Kevin Tewierek |
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| Rok vydání: | 2012 |
| Předmět: |
Protein Folding
Molecular Sequence Data Immunology Hepacivirus Plasma protein binding Biology medicine.disease_cause Microbiology Cell Line Conserved sequence chemistry.chemical_compound Viral Envelope Proteins Virology medicine Humans Amino Acid Sequence Cysteine Peptide sequence Conserved Sequence Cysteine metabolism Mutation Structure and Assembly Mutagenesis Virus Internalization Hepatitis C Biochemistry chemistry Insect Science Protein folding Protein Binding |
| Zdroj: | Journal of Virology. 86:3961-3974 |
| ISSN: | 1098-5514 0022-538X |
| DOI: | 10.1128/jvi.05396-11 |
| Popis: | 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. The phenotypes of individual cysteines and pairwise mutation of disulfides were largely the same for retrovirion-incorporated E2 and E2 661 , suggesting their disulfide arrangements are similar. However, the contributions of each cysteine residue and the nine disulfides to E2 structure and function varied. Individual Cys-to-Ala mutations revealed discordant effects, where removal of one Cys within a pair had minimal effect on H53 recognition and CD81 binding (C486 and C569) while mutation of its partner abolished these functions (C494 and C564). Removal of disulfides at C581-C585 and C452-C459 significantly reduced the amount of E1 coprecipitated with E2, while all other disulfides were absolutely required for E1E2 heterodimerization. Remarkably, E2 661 tolerates the presence of four free cysteines, as simultaneous mutation of C452A, C486A, C569A, C581A, C585A, C597A, and C652A (M+C597A) retained wild-type CD81 binding. Thus, only one disulfide from each of the three predicted domains, C429-C552 (DI), C503-C508 (DII), and C607-C644 (DIII), is essential for the assembly of the E2 661 CD81-binding site. Furthermore, the yield of total monomeric E2 increased to 70% in M+C597A. These studies reveal the contribution of each cysteine residue and the nine disulfide pairs to E2 structure and function. |
| Databáze: | OpenAIRE |
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