Table 2.
Phosphorylated lipid A species of P. gingivalisa
| Precursor ion | First deacylated ion mass | Fatty acid leaving group (R1) |
|---|---|---|
| m/z 1,620 | m/z 1,376 | 3-OH C14:0 |
| m/z 1,362 | 3-OH iso C15:0 | |
| m/z 1,634 | m/z 1,390 | 3-OH C14:0 |
| m/z 1,376 | 3-OH iso C15:0 | |
| m/z 1,362 | 3-OH C16:0 | |
| m/z 1,648 | m/z 1,390 | 3-OH iso C15:0 |
| m/z 1,376 | 3-OH C16:0 | |
| m/z 1,362 | 3-OH iso C17::0 | |
| m/z 1,662 | m/z 1,404 | 3-OH iso C15:0 |
| m/z 1,390 | 3-OH C16:0 | |
| m/z 1,376 | 3-OH iso C17::0 | |
| m/z 1,676 | m/z 1,418 | 3-OH iso C15:0 |
| m/z 1,404 | 3-OH C16:0 | |
| m/z 1,390 | 3-OH iso C17:0 | |
| m/z 1,690 | m/z 1,432 | 3-OH iso C15:0 |
| m/z 1,418b | 3-OH C16:0 | |
| m/z 1,404 | 3-OH iso C17:0 |
a
The lipid A preparation of P. gingivalis was subjected to electrospray-MS/MS, as described in Materials and Methods. Lipid A was dissolved in hexane-isopropanol-water, 6:8:0.75 (vol/vol/vol), at a concentration of approximately 0.5 μg/μl, and this solution was infused at a rate of 20 μl/min. Each precursor ion generates the indicated deacylated ions when the listed fatty acid is lost from the R1 position (Fig. 1). Though the fatty acid lost from the R1 position shown in Fig. 1 is 3-OH C16:0, other fatty acids can substitute in the R1 position as listed.
b
See Fig. 1B.