Occurrence of O-linked Xyl-GlcNAc and Xyl-Glc disaccharides in trocarin, a factor Xa homolog from snake venom.
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.
Joseph
J S
JS
Department of Biochemistry, Faculty of Medicine, National University of Singapore, Singapore.
Valiyaveettil
M
M
Gowda
D C
DC
Kini
R M
RM
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
D004187:Disaccharides; D004546:Elapid Venoms; C479573:Xyl-GlcNAc; C120393:trocarin; C061908:xylose-glucose; D011516:Prothrombin; D015951:Factor Xa; D000117:Acetylglucosamine