Title : Glycosylation
sites identified by solid-phase Edman degradation: O-linked glycosylation
motifs on human
glycophorin A
Abstract :
- The human red blood cell sialoglycoprotein , glycophorin A ( GpA ), contains a 'mucin-like' extensively O-glycosylated extracellular domain which carries the MN blood group antigens
- We have revised the sites of O-glycosylation in the extracellular domain of GpA by automated solid-phase Edman degradation, which allowed positive identification and quantitation of O-glycosylated Ser and Thr residues , as well as the single N-glycosylation site
- One N-linked and 16 O-linked sites were identified
- Carbohydrate was absent on Ser1, Ser14, Ser15, Ser23, Thr28 and Thr58 in GpA
- We propose that the glycosyltransferases present in erythrocytes recognize specific flanking sequences around potential O-glycosylation sites
- All 16 O-glycosylation sites are explained on the basis of four motifs
- Three motifs are associated with Thr-glycosylation: Xaa- Pro-Xaa-Xaa where at least one Xaa = Thr ; Thr-Xaa-Xaa-Xaa where at least one Xaa = Thr ; Xaa-Xaa- Thr-Xaa where at least one X = Arg or Lys
- The fourth motif is associated with Ser-glycosylation: Ser-Xaa-Xaa-Xaa where at least one Xaa = Ser
- These simple rules explain the glycosylation (or lack of it) on 21 of 22 Ser/Thr in the extracellular domain of GpA
Output (sent_index, trigger,
protein,
sugar,
site):
- 0. glycosylation, , -, -, motifs
- 1. sialoglycoprotein, , glycophorin A, -, -
- 1. sialoglycoprotein, , sialoglycoprotein, -, -
- 2. N-glycosylation, , -, -, site
- 2. O-glycosylated, , -, -, Ser and Thr residues
- 2. O-glycosylation, , GpA, -, domain
- 2. O-glycosylation, , GpA, -, site
- 2. O-glycosylation, , GpA, -, sites
- 2. Ser, , -, -, Ser and Thr residues
- 5. O-glycosylation, , -, -, sites
- 7. Thr-glycosylation, , -, -, Pro
- 7. Thr-glycosylation, , -, -, Thr
- 9. glycosylation, , -, -, Ser/Thr
- 9. glycosylation, , -, -, domain
- 9. glycosylation, , GpA, -, Ser/Thr
- 9. glycosylation, , GpA, -, domain
Output(Part-Of) (sent_index,
protein,
site):
- 0. glycophorin A, motifs
- 1. glycophorin A, domain
- 1. sialoglycoprotein, domain
- 2. GpA, domain
- 2. GpA, site
- 2. GpA, sites
- 4. GpA, Ser1, Ser14, Ser15, Ser23, Thr28 and Thr58
- 9. GpA, domain
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):