Table 1.
Glycosylation sites and amino acid sequences of high mannose glycopeptides observed in LC-MS/MS analysis of a tryptic digest of reduced and alkylated E2.
| Sitea | Tryptic peptide | Glycopeptide mass | Glycan typec | Relative abundanced | ||
|---|---|---|---|---|---|---|
| Theoretical | Observed | Mass accuracies
(ppm) |
||||
|
N66
(N448) |
65FNSSGCPER73b | 2106.798 | 2106.763 | 16 | Man 4 | 0.61 |
| 2268.851 | 2268.800 | 22 | Man 5 | 0.31 | ||
| 2430.904 | 2430.855 | 20 | Man 6 | 1 | ||
| 2592.956 | 2592.910 | 17 | Man 7 | 0.57 | ||
| 2755.008 | 2754.980 | 10 | Man 8 | 0.54 | ||
| 2917.060 | 2917.015 | 15 | Man 9 | 0.42 | ||
| 3079.112 | 3079.045 | 21 | Hex1Man9 | 0.38 | ||
| 3241.164 | 3241.115 | 15 | Hex2Man9 | 0.20 | ||
| 3403.216 | 3403.181 | 10 | Hex3Man9 | 0.15 | ||
|
N194
(N576) |
181VCGAPPCVIGGVGNNTLLCPTDCFRK206b | 4401.872 | 4401.825 | 11 | Man 7 | 0.6 |
| 4563.925 | 4563.867 | 13 | Man 8 | 1 | ||
| 4725.978 | 4725.930 | 10 | Man 9 | 0.44 | ||
|
N241
(N623) |
233LWHYPCTINYTIFK246b | 3071.428 | 3071.460 | 10 | Man 5 | 0.54 |
| 3233.482 | 3233.523 | 13 | Man 6 | 1 | ||
| 3395.435 | 3395.487 | 15 | Man 7 | 0.65 | ||
| 3557.487 | 3557.509 | 6 | Man 8 | 0.38 | ||
| 3719.539 | 3719.503 | 10 | Man 9 | 0.52 | ||
| 3881.591 | 3881.632 | 11 | Hex1Man9 | 0.44 | ||
| 4043.644 | 4043.664 | 5 | Hex2Man9 | 0.70 | ||
| 4205.696 | 4205.722 | 7 | Hex3Man9 | 0.47 | ||
|
N263
(N645) |
258LEAACNWTRGERCDLEDR275b | 3676.469 | 3676.497 | 8 | Man 7 | 0.25 |
| 3838.521 | 3838.589 | 17 | Man 8 | 0.30 | ||
| 4000.573 | 4000.600 | 7 | Man 9 | 0.70 | ||
| 4162.625 | 4162.650 | 6 | Hex1Man9 | 1 | ||
| 4324.677 | 4324.748 | 16 | Hex2Man9 | 0.45 | ||
| 4486.729 | 4486.758 | 8 | Hex3Man9 | 0.65 | ||
a
The numbers in parenthesis represent the positions of the N glycosylation sites which correspond to the positions in the HCV polyprotein of reference strain H (GenBank access number AF009606).
b
Represents a carboxymethylated cysteine residue.
c
The notation ManX indicates that X mannose residues are attached to the chitobiose core of each N-linked high mannose glycan.
d
The relative abundance was determined from deconvoluted mass spectrum over the mass range containing the glycopeptide ions corresponding to glycopeptides with the same amino acid sequence.