title: Structural properties of the ectodomain of hepatitis C virus E2 envelope protein.
abstract: We describe the structural and antigenic properties of a soluble form of hepatitis C virus E2 envelope protein ectodomain ending at residue 661 (E2(661)) which is obtained in large quantities in a baculovirus/insect cell system. The protein is secreted to the cellular medium by virus-infected cells. E2(661) is glycosylated and possesses a high tendency to self-associate. In fact, analytical ultracentrifugation and size exclusion chromatography studies show that the purified protein is mainly composed of dimers, trimers and tetramers being the dimer the smallest species present in solution. The secondary structure was determined by deconvolution of the far-UV circular dichroism spectrum yielding 8% alpha-helix structure, 47% extended structure and 45% non-ordered structure. The near-UV CD spectrum is indicative of a folded structure. The fluorescence emission spectrum indicates that Trp residues occupy a relatively low hydrophobic environment. Finally, E2(661) binds to a monoclonal conformation specific antibody and to antibodies present in human sera from HCV-positive patients. All these features suggest that the secreted protein possesses a native-like conformation. The use of this independent folding domain may contribute to shed light on the biology of HCV and could also be used as a vaccine in the prevention of HCV infection.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Rodríguez-Rodríguez
authors.forename: Daniel
authors.initials: D
authors.lastname: Tello
authors.forename: Belén
authors.initials: B
authors.lastname: Yélamos
authors.forename: Julián
authors.initials: J
authors.lastname: Gómez-Gutiérrez
authors.forename: Beatriz
authors.initials: B
authors.lastname: Pacheco
authors.forename: Sara
authors.initials: S
authors.lastname: Ortega
authors.forename: Alicia G
authors.initials: AG
authors.lastname: Serrano
authors.forename: Darrell L
authors.initials: DL
authors.lastname: Peterson
authors.forename: Francisco
authors.initials: F
authors.lastname: Gavilanes
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D015967:Gene Expression Regulation, Viral; D006031:Glycosylation; D016174:Hepacivirus / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013057:Spectrum Analysis; D014759:Viral Envelope Proteins / Q000737:chemistry*
chemical_list: D000956:Antigens, Viral; D000939:Epitopes; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins