Table 1.
Partial sequences determined from the mass of fragmentation ions for a triply charge precursor ion at the retention time of 91.17 min with m/z 1351.33 (molecular mass at 4048.963 Da). The longest b- and y-ions observed are underlined. All Cys are alkylated with IAA. The adjoining residues before cleavage are in parenthesis. 18O-labeling indicated that ions 1 and 2 are b-ions and ion 3 to 11 are y-ions. The crosslinked peptides were determined to be HC:G118-R129/HC:C215-K240
| # | m/z | Charge | User mass (Da) |
Theor.mass (Da) |
Δmass (ppm) |
peptide | Corresponding Tryptic Peptide |
Notes | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Sequence | Mass | |||||||||
| 1 | 470.2368 | 1 | 505.251 | 505.254 | 5.1 | (K) GPSVF(P) |
(K)118GPSVFPLAPCSR129/(S) |
1287.6282 | Chain 2 | |
| 2 | 769.4172 | 1 | 786.420 | 786.428 | 9.6 | (K) GPSVFPLA(P) |
||||
| 3 | 566.3647 | 1 | 565.357 | 565.359 | 3.1 | (F)PPKPK(D) |
(K) 215CCVECPPCPAPPVAGPSVFLFPPKPK240(D) |
2911.3305 | Chain 1 | |
| 4 | 1313.7528 | 1 | 1312.745 | 1312.754 | 7.0 | (A)GPSVFLFPPKPK(D) |
||||
| 5 | 1384.7951 | 1 | 1383.788 | 1383.791 | 2.4 | (V)AGPSVFLFPPKPK(D) |
||||
| 6 | 839.4851 | 2 | 1676.956 | 1676.965 | 5.5 | (A)PPVAGPSVFLFPPKPK(D) |
||||
| 7 | 1846.0661 | 1 | 1845.042 | 1845.055 | 7.1 | (C)PAPPVAGPSVFLFPPKPK(D) |
||||
| 8 | 923.5283 | 2 | 1845.059 | 1845.055 | −2.0 | (C)PAPPVAGPSVFLFPPKPK(D) |
||||
| 9 | 1101.0885 | 2 | 2200.162 | 2200.175 | 6.0 | (C)PPCPAPPVAGPSVFLFPPKPK(D) |
||||
| 10 | 1181.5930 | 2 | 2361.171 | 2361.190 | 8.0 | (E)CPPCPAPPVAGPSVFLFPPKPK(D) |
||||
| 11 | 1688.7689 | 1 | 1705.772 | 1705.788 | 9.4 | (V)HQDWLNGKEYKCK(V) |
(R) 294VVSVLTVVHQDWLNGKEYKCK314(V) |
2502.2941 | ruled out for chain 2, see text |
|