PMID: PMC4084840-1-7

 

    Legend: Gene, Sites

Title : O-Glycopeptide Microheterogeneity in Recombinant ITIH4

Abstract :

1. We also characterized several O-glycopeptides in recombinantand serum-derived ITIH4
2. Recombinant ITIH4 is glycosylated on overlappingpeptides IPKPEASFSPR ( residues 634–644) and ASFSPR( residues 639–644) containing potentially glycosylated residuesS640 and S642
3. We identified two major glycoforms of this peptide ,including HexNAc1Hex1NeuAc1 and HexNAc1HexNAc1NeuAc2, and several minor glycoforms (Table 3)
4. To complement these analyses, we selectively detached O-glycans fromrecombinant ITIH4 via reductive beta-elimination and then performedMS and MS/MS analyses on detached, permethylated O-glycans (Supplementary Figure 1B, Supporting Information)
5. We detected simple O-glycan structures, including HexNAc1Hex1NeuAc1 and HexNAc1HexNAc1NeuAc2, equivalent to theglycan com positions on IPKPEASFSPR and ASFSPR
6. Therefore,we suggest that it is likely that only one of the potential O-glycosylationsites on this peptide (either S640 or S642) is glycosylated
7. We alsoidentified a second glycopeptide , GPDVLTATVSGK, spanningresidues 501–512, with multiple glycoforms (Table 3), including HexNAc1Hex1NeuAc2 and HexNAc2HexNAc2NeuAc2.
8. Because we detect only simple O-glycans in our detachedglycan analysis, and we detect glycopeptides with higher com positions on glycopeptide GPDVLTATVSGK, we suggest that at leasttwo of the potentially O-glycosylated residues on this peptide (T506,T508, S510) are glycosylated with simple O-glycans
9. We also detectedtwo fucosylated O-glycopeptides on GPDVLTATVSGK from recombinant ITIH4
10. We did not detect fucosylated O-glycans in our detached glycananalyses, suggesting that fucosylated O-glycans were below the limitof detection
11. The recombinant ITIH4 protein sequence differsfrom the canonical sequence in UniProt (Q14624) at residues 85 (Ito N) and 698 (P to T)
12. We detect multiple glycoforms of peptide LAILPASATPATSNPDPAVSR ( residues 690–710)
13. NonsialylatedO-glycopeptides including HexNAc1, HexNAc2,HexNAc1Hex1, HexNAc2Hex2, HexNAc3Hex4 and HexNAc4Hex4 account for over half of the glycoforms (basedon relative intensity) of this peptide ; we also detect com positions consistent with simple sialylated O-glycans including HexNAc1Hex1NeuAc2, HexNAc3Hex3NeuAc3, and HexNAc4Hex4NeuAc4 (Table 3A)
14. In addition, we detect a third (partially overlapping) glycopeptide ,PAVSRVMNMK + HexNAc1HexNAc1NeuAc2 in trypsin-chymotrypsin digests of recombinant ITIH4
15. This peptide contains a single potential glycosylation siteat S709
16. We have identified multiple O-glycoforms on three differentpeptides in trypsin- GluC and trypsin-chymotrypsin digests of recombinant ITIH4

Output (sent_index, trigger, protein, sugar, site):

• 1. O-glycopeptides, , -, -, O-glycopeptides
• 12. glycoforms, , -, -, residues
• 13. NonsialylatedO-glycopeptides, , -, -, NonsialylatedO-glycopeptides
• 13. glycoforms, , -, -, peptide
• 13. sialylated, , -, HexNAc1Hex1NeuAc2, -
• 13. sialylated, , -, HexNAc3Hex3NeuAc3, -
• 13. sialylated, , -, HexNAc4Hex4NeuAc4, -
• 14. glycopeptide, , -, -, glycopeptide
• 16. O-glycoforms, , -, -, differentpeptides
• 2. glycosylated, , -, -, residues
• 2. glycosylated, , -, -, residuesS640
• 2. glycosylated, , Recombinant ITIH4, -, residues
• 3. glycoforms, , -, -, peptide
• 3. peptide, , -, HexNAc1Hex1NeuAc1, peptide
• 3. peptide, , -, HexNAc1HexNAc1NeuAc2, peptide
• 6. glycosylated, , -, -, O-glycosylationsites
• 7. glycopeptide, , -, HexNAc1Hex1NeuAc2, glycopeptide
• 7. glycopeptide, , -, HexNAc2HexNAc2NeuAc2, glycopeptide
• 8. O-glycosylated, , -, -, residues
• 8. glycopeptide, , -, -, glycopeptide
• 8. glycopeptides, , -, -, glycopeptides
• 9. O-glycopeptides, , -, -, O-glycopeptides
• 9. fucosylated, , -, -, O-glycopeptides

Output(Part-Of) (sent_index, protein, site):

• 1. ITIH4, O-glycopeptides
• 11. ITIH4, sequence

*Output_Site_Fusion* (sent_index, protein, sugar, site):

 

Protein	NCBI ID	SENTENCE INDEX