title: Identification of new functional regions in hepatitis C virus envelope glycoprotein E2.
abstract: Little is known about the structure of the envelope glycoproteins of hepatitis C virus (HCV). To identify new regions essential for the function of these glycoproteins, we generated HCV pseudoparticles (HCVpp) containing HCV envelope glycoproteins, E1 and E2, from different genotypes in order to detect intergenotypic incompatibilities between these two proteins. Several genotype combinations were nonfunctional for HCV entry. Of interest, a combination of E1 from genotype 2a and E2 from genotype 1a was nonfunctional in the HCVpp system. We therefore used this nonfunctional complex and the recently described structural model of E2 to identify new functional regions in E2 by exchanging protein regions between these two genotypes. The functionality of these chimeric envelope proteins in the HCVpp system and/or the cell-cultured infectious virus (HCVcc) was analyzed. We showed that the intergenotypic variable region (IgVR), hypervariable region 2 (HVR2), and another segment in domain II play a role in E1E2 assembly. We also demonstrated intradomain interactions within domain I. Importantly, we also identified a segment (amino acids [aa] 705 to 715 [segment 705-715]) in the stem region of E2, which is essential for HCVcc entry. Circular dichroism and nuclear magnetic resonance structural analyses of the synthetic peptide E2-SC containing this segment revealed the presence of a central amphipathic helix, which likely folds upon membrane binding. Due to its location in the stem region, segment 705-715 is likely involved in the reorganization of the glycoprotein complexes taking place during the fusion process. In conclusion, our study highlights new functional and structural regions in HCV envelope glycoprotein E2.
authors.affiliation: Institut Pasteur de Lille, Center for Infection and Immunity of Lille, F-59019 Lille, France.
authors.forename: Anna
authors.initials: A
authors.lastname: Albecka
authors.forename: Roland
authors.initials: R
authors.lastname: Montserret
authors.forename: Thomas
authors.initials: T
authors.lastname: Krey
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Tarr
authors.forename: Eric
authors.initials: E
authors.lastname: Diesis
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Ball
authors.forename: Véronique
authors.initials: V
authors.lastname: Descamps
authors.forename: Gilles
authors.initials: G
authors.lastname: Duverlie
authors.forename: Felix
authors.initials: F
authors.lastname: Rey
authors.forename: François
authors.initials: F
authors.lastname: Penin
authors.forename: Jean
authors.initials: J
authors.lastname: Dubuisson
mesh_terms: D000595:Amino Acid Sequence; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D005838:Genotype; D057809:HEK293 Cells; D016174:Hepacivirus / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000378:metabolism*; D053586:Virus Internalization
chemical_list: C087035:E1 protein, Hepatitis C virus; D010455:Peptides; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; C091015:glycoprotein E2, Hepatitis C virus