TABLE 3.
Summary of LC-ESI-MS/MS analysis of the glycosylation of human erythropoietin, AcrA, and CtxB co-expressed with ApNGT in the cytoplasm of E. coli
Modified residues are underlined and in bold. (Annotated spectra are shown in supplemental Fig. S3.)
| Site | Observed m/z | Error | Mascot Score | Peptide sequence | Sequencing method |
|---|---|---|---|---|---|
| ppm | |||||
| Human erythropoietin | |||||
| Asn51 or Asn65 | 1483.1589 (2+) | 2.29 | 37 | K.EAENITTGCAEHCSLNENITVPDTK.V | CID |
| K.EAENITTGCAEHCSLNENITVPDTK.V | |||||
| Asn51 and Asn65 | 1043.1256 (3+) | 1.82 | 22 | K.EAENITTGCAEHCSLNENITVPDTK.V | CID |
| Asn110 | 841.1046 (3+) | 2.32 | 70 | R.GQALLVNSSQPWEPLQLHVDK.A | CID |
| C. jejuni efflux pump subunit AcrA | |||||
| Asn254 | 973.1572 (3+) | 3.5 | 81 | K.AVFDNNNSTLLPGAFATITSEGFIQK.N | CID/HCD |
| Cholera toxin subunit B (CtxB) | |||||
| Asn25 | 1510.1835 (2+) | 3.8 | 101 | -MTPQNITDLCAEYHNTQIHTLNDK.I | CID |