title: Interferon-gamma receptor extracellular domain-IgG fusion protein produced in Chinese hamster ovary cells as mixture of glycoforms.
abstract: Glycosylation of proteins fulfills important functions and because of its diversity contributes to apparent protein heterogeneity. We investigated the heterogeneity of a fusion protein comprising the extracellular domain of the human interferon-gamma (IFN-gamma) receptor and parts of the human IgG3 constant region, a potential IFN-gamma antagonist. The protein was produced in Chinese hamster ovary (CHO) cells and was secreted into the culture medium as an 175 kD glycoprotein. Glycosylation represented approximately one-third of the apparent molecular mass of the fusion protein, consisted of N- and O-linked carbohydrate moieties, and included sialic acid residues as part of both N- and O-linked oligosaccharides. Fusion protein forms with different apparent molecular masses and charges were separated by ion-exchange chromatography. Preparative electrofocusing revealed a wide spectrum of glycoforms. Glycosylation of the fusion protein and of soluble IFN-gamma receptors, comprising the extracellular domain of the native sequence, expressed in insect and CHO cells did not interfere with affinity of ligand binding.
authors.affiliation: F. Hoffmann-La Roche, Ltd., Basel, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Mesa
authors.forename: Z
authors.initials: Z
authors.lastname: Dembic
authors.forename: G
authors.initials: G
authors.lastname: Garotta
authors.forename: M
authors.initials: M
authors.lastname: Fountoulakis
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D006031:Glycosylation; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis / Q000235:genetics*; D007371:Interferon-gamma / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D017434:Protein Structure, Tertiary; D017471:Receptors, Interferon / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012995:Solubility
chemical_list: D007074:Immunoglobulin G; D017471:Receptors, Interferon; D011993:Recombinant Fusion Proteins; D007371:Interferon-gamma