Table 2.
The molecular mass of the nisin mutants after tryptophan analogues are incorporated
| Mutants | Modifications | Predicted mass (Da) | Observed mass (Da) of main peaks at different culture conditions | |||
|---|---|---|---|---|---|---|
| Trp | 5FW | 5HW | 5MeW | |||
| I1W | −8H2O | 5757.750 | 5757.747 | |||
| +F −8H2O | 5775.741 | 5775.752 | ||||
| +OH −8H2O | 5773.745 | 5773.737 | ||||
| +Me −8H2O | 5771.766 | 5771.752 | ||||
| I4W | −8H2O | 5757.750 | 5757.735 (7)a | 5757.776 (9) | 5757.795 (2) | 5757.789 (30) |
| −7H2O | 5775.761 | 5775.724 (69) | ||||
| −7H2O + Oxi | 5791.756 | 5791.726 (24) | ||||
| +F −8H2O | 5775.741 | 5775.734 (59) | ||||
| +F −8H2O + Oxi | 5791.736 | 5791.733 (30) | ||||
| +OH −8H2O | 5773.745 | 5773.766 (35) | ||||
| +OH −7H2O | 5791.756 | 5791.753 (14) | ||||
| +OH −8H2O + Oxi | 5789.740 | 5789.751 (24) | ||||
| +OH −8H2O + 2Oxi | 5807.751 | 5807.743 (20) | ||||
| +Me −8H2O | 5771.766 | 5771.758 (33) | ||||
| +Me −7H2O | 5789.776 | 5789.765 (36) | ||||
| M17W | −8H2O | 5739.794 | 5739.763 | |||
| +F −8H2O | 5757.784 | 5757.791 | ||||
| +OH −8H2O | 5755.794 | 5755.727 (30) | ||||
| +OH −8H2O + Oxi | 5771.789 | 5771.751 (65) | ||||
| +Me −8H2O | 5753.809 | 5753.749 | ||||
| V32W | −8H2O | 5771.766 | 5771.757 (30) | |||
| −7H2O | 5789.776 | 5789.768 (60) | ||||
| +F −8H2O | 5789.756 | 5789.752 (14) | ||||
| +F −7H2O | 5807.767 | 5807.759 (36) | ||||
| +F −8H2O + Oxi | 5805.751 | 5805.754 (8) | ||||
| +F −7H2O + Oxi | 5823.762 | 5823.756 (33) | ||||
| +OH −8H2O | 5787.761 | NDb | ||||
| +Me −8H2O | 5785.781 | NDb | ||||
a The values between brackets refer to the percentage of different variants; similarly hereinafter
b ND Not detected