Title : Identification of N-linked glycosylation and
putative O-fucosylation, C-mannosylation sites in plasma derived
ADAMTS13
Abstract :
- BACKGROUND: Acquired deficiency of ADAMTS13 causes a rare and life-threatening disorder called thrombotic thrombocytopenic purpura ( TTP )
- Several studies have shown that aberrant glycosylation can play an important role in the pathogenesis of autoimmune diseases.N-linked glycosylation and putative O-fucosylation sites have been predicted or identified in recombinant ADAMTS13
- However, it is not known which of these sites are glycosylated in plasma derived ADAMTS13
- OBJECTIVES: Here we investigated the presence of putative O-fucosylation, C-mannosylation and N-linked glycosylation sites on plasma derived ADAMTS13
- METHODS/RESULTS: Sites of N-linked glycosylation were determined by the use of peptide N-glycosidase-F (PNGase F), which removes the entire carbohydrate from the side chain of asparagines
- Nine of the 10 predicted N-linked glycosylation sites were identified in or near the metalloproteinase,spacer, thrombospondin type 1 repeat ( TSR1 ) and the CUB domain of plasma ADAMTS13
- Moreover, six putative O-fucosylated sites were identified in the TSR domains of plasma ADAMTS13 by performing searches of the tandem mass spectrometry (MS/MS) data for loss of hexose (162 Da), deoxyhexose (146 Da), or hexose deoxyhexose(308 Da)
- The use of electron transfer dissociation (ETD) allowed for unambiguous identification of the modified sites
- In addition to putative O-fucosylation and N-linked glycosylation, two putative C-mannosylation sites were identified within the TSR1 and TSR4 domains of ADAMTS13
- CONCLUSIONS: Our data identify several glycosylation sites on plasma derived ADAMTS13
- We anticipate that our findings may be relevant for the initiation of autoimmune reactivity against ADAMTS13 in patients with acquired TTP