title: Alanine scanning mutagenesis of hepatitis C virus E2 cysteine residues: Insights into E2 biogenesis and antigenicity.
abstract: Envelope glycoprotein 2 (E2) of hepatitis C virus contains 18 conserved cysteine (Cys) residues in its ectodomain. By cysteine-alanine mutagenesis and function analysis, six Cys in H77 E2 (C494, C508, C552, C564, C607 and C644) were found to be indispensable for recognition by conformation-dependent mAb H53. Removal of any of these Cys residues did not affect E2 heterodimerization with E1, but notably reduced E1E2 transmembrane transportation. These Cys together with C429 and C503 were required for conformation-dependent mAb H48 recognition. All of the above Cys except C607 were required for H77 and Con1 E2 binding to CD81. None of individual mutation of above Cys affected the ability of E2 to induce neutralizing antibodies in mice. Mouse antibodies mainly recognize E2 linear epitopes and are unrelated to epitopes recognized by human E2 antibodies. The findings provide new insights for understanding the biogenesis of functional HCV envelope proteins and HCV neutralizing immunity.
authors: Department of Microbiology, Second Military Medical University, 800 Xiangyin Road, Shanghai 200433, China.
authors: Wenbo
authors: W
authors: Wang
authors: Mo
authors: M
authors: Guan
authors: Yuan
authors: Y
authors: Liu
authors: Qingqiang
authors: Q
authors: Xu
authors: Haoran
authors: H
authors: Peng
authors: Xiaoqing
authors: X
authors: Liu
authors: Ziwei
authors: Z
authors: Tang
authors: Yongzhe
authors: Y
authors: Zhu
authors: Dage
authors: D
authors: Wu
authors: Hao
authors: H
authors: Ren
authors: Ping
authors: P
authors: Zhao
authors: Zhongtian
authors: Z
authors: Qi
mesh_terms: D000409:Alanine / Q000235:genetics*; D019943:Amino Acid Substitution; D000914:Antibodies, Viral / Q000276:immunology; D003545:Cysteine / Q000235:genetics*; D016174:Hepacivirus / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D006526:Hepatitis C / Q000276:immunology / Q000821:virology*; D006801:Humans; D016296:Mutagenesis; D060225:Tetraspanin 28 / Q000276:immunology; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D060225:Tetraspanin 28; D014759:Viral Envelope Proteins; D003545:Cysteine; D000409:Alanine
keywords: Antigenicity; CD81 binding; Cysteine; Disulfide bond; E1E2 heterodimers; Envelope protein 2; HCVpp; Hepatitis C virus