title: Delta-peptide is the carboxy-terminal cleavage fragment of the nonstructural small glycoprotein sGP of Ebola virus.
abstract: In the present study we have investigated processing and maturation of the nonstructural small glycoprotein (sGP) of Ebola virus. When sGP expressed from vaccinia virus vectors was analyzed by pulse-chase experiments using SDS-PAGE under reducing conditions, the mature form and two different precursors have been identified. First, the endoplasmic reticulum form sGP(er), full-length sGP with oligomannosidic N-glycans, was detected, sGP(er) was then replaced by the Golgi-specific precursor pre-sGP, full-length sGP containing complex N-glycans. This precursor was finally converted by proteolysis into mature sGP and a smaller cleavage fragment, Delta-peptide. Studies employing site-directed mutagenesis revealed that sGP was cleaved at a multibasic amino acid motif at positions 321 to 324 of the open reading frame. Cleavage was blocked by RVKR-chloromethyl ketone. Uncleaved pre-sGP forms a disulfide-linked homodimer and is secreted into the culture medium in the presence of the inhibitor as efficiently as proteolytically processed sGP. In vitro treatment of pre-sGP by purified recombinant furin resulted in efficient cleavage, confirming the importance of this proprotein convertase for the processing and maturation of sGP. Delta-peptide is also secreted into the culture medium and therefore represents a novel nonstructural expression product of the GP gene of Ebola virus. Both cleavage fragments contain sialic acid, but only Delta-peptide is highly O-glycosylated.
authors.affiliation: Institut für Virologie, Philipps-Universität Marburg, Marburg, 35011, Germany.
authors.forename: V A
authors.initials: VA
authors.lastname: Volchkova
authors.forename: H D
authors.initials: HD
authors.lastname: Klenk
authors.forename: V E
authors.initials: VE
authors.lastname: Volchkov
mesh_terms: D000595:Amino Acid Sequence; D019281:Dimerization; D029043:Ebolavirus / Q000737:chemistry* / Q000235:genetics; D006023:Glycoproteins / Q000737:chemistry* / Q000235:genetics; D006031:Glycosylation; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010446:Peptide Fragments / Q000737:chemistry*; D011499:Protein Processing, Post-Translational; D012794:Sialic Acids / Q000378:metabolism; D014162:Transfection; D014764:Viral Proteins
chemical_list: D006023:Glycoproteins; D010446:Peptide Fragments; D012794:Sialic Acids; D014764:Viral Proteins; C110613:secreted glycoprotein, Ebola virus