Table 2.
Detection by MALDI-TOF and nanos pray LC-MS/MS of peptides from the final elution sample after CNBr digestion.
| Fragments (residue number in Ste2p-rho) | Calculated Massa | MALDI/TOF Observed Mass [M +H]+1 | Nanospray Observed Mass [M +H]+1 | Method of Detection |
|---|---|---|---|---|
| 181 – 189 | 953.1 | NDb | 953.6 | NSd |
| 155 – 165 | 1203.4 | ND | 1204.4 | NS |
| 398 – 409 | 1333.8 | ND | 1334.5 | NS |
| 55 – 69 | 1457.7 | 1458.8 | 1458.0 | Bothe |
| 295 – 311 | 1765.9 | ND | 1766.2 | NS |
| 55 – 71 | 1775.2 | 1793.1c | ND | MALDI |
| 389 – 410 | 2264.5 | ND | 2263.9 | NS |
| 166 – 189 | 2490.0 | 2507.6c | ND | MALDI |
| 190 – 218 | 3179.5 | 3180.6 | 3181.0 | Both |
| 410 – 438 | 3255.4 | 3255.5 | 3255.4 | Both |
| 219 – 250 | 3726.6 | 3725.8 | ND | MALDI |
| 181 – 218 | 4162.7 | 4177.2c | ND | MALDI |
| 251 – 294 | 4555.4 | ND | 4556.8 | NS |
| 166 – 218 | 5699.5 | 5714.7c | ND | MALDI |
a
The mass for the CNBr generated peptide fragments, some are partial cleavage products, were calculated using homoserine lactone as the C-terminal amino acid, except for 410-438, which is the C-terminus of Ste2p-rho.
b
Not detected.
c
Under the conditions of partial CNBr cleav age, internal methionine-sulfoxide is generated. Thus, the partially cleaved peptide fragments of Ste2p-rho are 16 Da larger than the size reported by the program for peptides.
d
Detected by nanospray-LC-MS/MS (NS).
e
Detected by both MALDI-TOF and nanospray.