title: Occurrence of O-linked Xyl-GlcNAc and Xyl-Glc disaccharides in trocarin, a factor Xa homolog from snake venom.
abstract: Trocarin is a 46515-Da group D prothrombin-activating glycoprotein from the venom of the Australian elapid, Tropidechis carinatus. Amino acid sequencing and functional characterization of trocarin demonstrated that it is a structural and functional homolog of mammalian blood coagulation factor (F)Xa. In this study we show that, in contrast to mammalian Xa, which is not glycosylated, trocarin contains an O-linked carbohydrate moiety in its light chain and an N-linked carbohydrate oligosaccharide in its heavy chain. Mass spectrometry and sugar compositional analysis indicate that the O-linked carbohydrate moiety is a mixture of Xyl-GlcNAc-, GlcNAc-, Xyl-Glc- and Glc- structures linked to Ser 52. The N-linked carbohydrate on Asn 45 of the heavy chain is a sialylated, diantennary oligosaccharide that is located at the lip of the active site of the prothrombin activator.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore.
authors.forename: J S
authors.initials: JS
authors.lastname: Joseph
authors.forename: M
authors.initials: M
authors.lastname: Valiyaveettil
authors.forename: D C
authors.initials: DC
authors.lastname: Gowda
authors.forename: R M
authors.initials: RM
authors.lastname: Kini
mesh_terms: D000117:Acetylglucosamine / Q000378:metabolism; D002240:Carbohydrate Sequence; D004187:Disaccharides / Q000032:analysis*; D004546:Elapid Venoms / Q000096:biosynthesis / Q000737:chemistry; D015951:Factor Xa; D006031:Glycosylation; D006056:Golgi Apparatus; D006801:Humans; D008969:Molecular Sequence Data; D011499:Protein Processing, Post-Translational; D011516:Prothrombin / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry
chemical_list: D004187:Disaccharides; D004546:Elapid Venoms; C479573:Xyl-GlcNAc; C120393:trocarin; C061908:xylose-glucose; D011516:Prothrombin; D015951:Factor Xa; D000117:Acetylglucosamine