Table 1.
The main ion peaks observed in the MALDI-TOF MS spectrum reported in Fig. 1, the predicted mass and the proposed interpretation of the substituting fatty acids and phosphates on the P. pulmonicola RL8228 lipid A backbone
| Predicted mass (Da) | Observed ion peaks (m/z) | Acyl substitution | Proposed fatty acid/phosphate composition |
|---|---|---|---|
| 1098.69 | 1098.16 | Tri-acyl | HexN2P [14:0(3-OH)]3 |
| 1178.66 | 1178.16 | Tri-acyl | HexN2P2 [14:0(3-OH)]3 |
| 1296.86 | 1296.41 | Tetra-acyl | HexN2P [14:0(3-OH)]3[12:0(2-OH)] |
| 1376.82 | 1376.35 | Tetra-acyl | HexN2P2 [14:0(3-OH)]3[12:0(2-OH)] |
| 1456.92 | 1457.48 | Tetra-acyl | HexN3P [14:0(3-OH)]3[12:0(2-OH)] |
| 1523.05 | 1522.62 | Penta-acyl | HexN2P [14:0(3-OH)]3[12:0(2-OH)] [14:0(2-OH)] |
| 1537.89 | 1537.50 | Tetra-acyl | HexN3P2 [14:0(3-OH)]3[12:0(2-OH)] |
| 1603.02 | 1602.59 | Penta-acyl | HexN2P2 [14:0(3-OH)]4[12:0(2-OH)] |
| 1684.12 | 1683.75 | Penta-acyl | HexN3P [14:0(3-OH)]4[12:0(2-OH)] |
The observed masses reported in the table are compared to the calculated molecular weight (predicted mass, Da) of each ion based on the proposed lipid A structures.