PMID: PMC4739677-1-9

 

    Legend: Gene, Sites

Title : α-2-HS-glycoprotein

Abstract :
  1. In this study, the majority of identified O-glycopeptides were derived from α-2-HS-glycoprotein , also known as fetuin-A
  2. Fetuin-A is a negative acute phase glycoprotein that is highly abundant in fetal blood plasma
  3. It is involved in transport and storage of substances and features three O-glycosylation sites ( Thr256, Thr270, Ser346 ), which are decorated with sialylated mucin-type core 1 O-glycan structures (30, 58, 59)
  4. In contrast to previous reports (30, 58), intact O-glycopeptides identified and characterized in the present study describe all three known fetuin-A O-glycosylation sites including the attached O-glycans (mono- and disialylated mucin-type core 1 O-glycans), respectively
  5. By pinpointing O-glycosylation sites using ETD, the reported ETD Biotools scores can be misleading
  6. This for instance holds true for the fetuin-A O-glycopeptide 252QPVTSQPQPE262 (m/z 623.233+) and its three potential O-glycosylation sites : Thr252 (669), Thr256 (412), Thr257 (362) (supplemental Fig
  7. S7)
  8. According to the score values T252 would be the occupied site ; the presence of characteristic ETD fragment ions at m/z 344.011+ (c3), 1200.451+ (c5), 1287.471+ (c6), 1525.571+ (z+18), 1751.511+ (z+210), though, clearly indicates the occupancy of Thr256 , which is in agreement with literature findings
  9. For the two other described fetuin-A O-glycosylation sites Thr270 and Ser346 ETD fragmentation was actually not mandatory, because corresponding O-glycopeptides were identified that solely harbor one O-glycosylation site (e.g. Thr270 : 267AVPPV272, Ser346 : 342VVQPVG348), respectively
  10. Also of note, with respect to the peptide identification, b- and y-ions were detected in the CID-MS2 fragment spectra of the fetuin-A O-glycopeptides 252TQPVSQPQPE262 (m/z 623.233+), 267AVPPVVDPDAPPSPPL283 (m/z 872.723+) and 266EAVPPVVDPDAPPSPPL283 (m/z 915.713+), which already permit the unambiguous peptide identification without consideration of CID-MS3 spectra (supplemental Figs
  11. S5–S7)
  12. Furthermore, internal glycopeptide fragment ions resulting from concerted fragmentations along the peptide backbone and along the glycan moiety were detected in the same CID-MS2 spectra - a low-energy CID glycopeptide fragmentation event that is rarely described in literature (e.g.252TQPV(HexNAc1Hex1NeuAc1)SQPQPE262 → 252TQPV(HexNAc)SQ258m/z 945.351+) (supplemental Fig
  13. S7)
Output (sent_index, trigger, protein, sugar, site):
  • 0. α-2-HS-glycoprotein, , α-2-HS-glycoprotein, -, -
  • 1. O-glycopeptides, , -, -, O-glycopeptides
  • 1. α-2-HS-glycoprotein, , α-2-HS-glycoprotein, -, -
  • 10. O-glycopeptides, , -, -, O-glycopeptides
  • 12. glycopeptide, , -, -, glycopeptide
  • 2. glycoprotein, , Fetuin-A, -, -
  • 2. glycoprotein, , glycoprotein, -, -
  • 3. O-glycosylation, , -, -, sites
  • 3. substances, , -, -, Thr256, Thr270, Ser346
  • 3. substances, , -, -, sites
  • 4. O-glycopeptides, , -, -, O-glycopeptides
  • 4. O-glycosylation, , -, -, sites
  • 5. O-glycosylation, , -, -, sites
  • 6. O-glycopeptide, , -, -, O-glycopeptide
  • 6. O-glycosylation, , -, -, sites
  • 6. sites, , -, -, Thr252 (669), Thr256 (412), Thr257 (362)
  • 8. occupancy, , -, -, Thr256
  • 9. O-glycopeptides, , -, -, O-glycopeptides
  • 9. O-glycosylation, , -, -, site
  • 9. O-glycosylation, , -, -, sites Thr270 and Ser346
  • 9. site, , -, -, Ser346
Output(Part-Of) (sent_index, protein, site):
  • 10. fetuin-A, O-glycopeptides
  • 4. fetuin-A, sites
  • 9. fetuin-A, sites Thr270 and Ser346
*Output_Site_Fusion* (sent_index, protein, sugar, site):
  • 3. fetuin-A, -, Thr256, Thr270, Ser346
  • 6. fetuin-A, -, Thr252 (669), Thr256 (412), Thr257 (362)
  • 8. fetuin-A, -, Thr256
  • 9. fetuin-A, -, Ser346
  • 9. fetuin-A, -, sites Thr270 and Ser346

 

 

Protein NCBI ID SENTENCE INDEX