TABLE 2.
Peptide mapping of SSO1353
Characteristic peptide molecular ions containing residue E at position 335 observed during nano-HPLC-ESI-MS/MS IDA analyses of SSO1353 incubated in the absence and in the presence of 2,4DNp-2F-Glc inhibitor and digested by pepsin. Peptide sequences (both unmodified and modified) were elucidated by the interpretation of nano-ESI-MS/MS spectra acquired on the doubly charged (z = 2) precursor ions (Fig. 4). Modification corresponds to the covalent attachment of 2F-Glc ligand at E335 (indicated in the sequence as E*).
| From-To | Unmodified and modified peptide sequences | Mw (calc.) | SSO1353 |
SSO1353 inhibited |
||||
|---|---|---|---|---|---|---|---|---|
| Rt | m/z | Intensity | Rt | m/z | Intensity | |||
| min | cps | min | cps | |||||
| 332–345 | AIYEAPQNCPYLGT | 1538.708 | 20.7 | 770.36 | 26 | 21.2 | 770.36 | 10 |
| AIYE*APQNCPYLGT | 1703.188 | – | n.d.a | – | 852.39 | 34 | ||
| 332–343 | AIYEAPQNCPYL | 1380.638 | 21.8 | 691.33 | 30 | 22.0 | 691.33 | 17 |
| AIYE*APQNCPYL | 1544.689 | – | n.d. | – | 773.35 | 44 | ||
| 332–347 | AIYEAPQNCPYLGTIG | 1708.813 | 23.2 | 855.42 | 42 | 23.2 | 855.42 | 16 |
| AIYE*APQNCPYLGTIG | 1873.293 | – | n.d. | – | 937.44 | 37 | ||
| 332–348 | AIYEAPQNCPYLGTIGA | 1779.85 | 23.5 | 890.94 | 280 | 23.7 | 890.93 | 63 |
| AIYE*APQNCPYLGTIGA | 1943.898 | – | n.d. | – | 972.96 | 240 | ||
| 332–349 | AIYEAPQNCPYLGTIGAC | 1882.859 | 24.8 | 942.46 | 320 | 24.6 | 942.44 | 106 |
| AIYE*APQNCPYLGTIGAC | 2046.07 | – | n.d. | – | 1024.46 | 384 | ||
| 332–340 | AIYEAPQNC | 1007.447 | – | n.d. | – | 25.2 | n.d. | – |
| AIYE*APQNC | 1171.495 | – | n.d. | – | 586.76 | 94 | ||
a n.d., not determined.