TABLE 2.
Negative-ion MS data and proposed compositions of O-deacylated LPS from N. gonorrhoeae strains MS11, 1291, FA19, and F62a
| Strain | Observed ions (m/z)
|
Molecular mass (Da)b
|
Relative intensityc | Proposed composition | ||
|---|---|---|---|---|---|---|
| (M-2H)2− | (M-3H)3− | Observed | Calculated | |||
| MS11 | 1496.3 | 997.7 | 2,996.1 | 2,995.8 | 1.0 | 3Hex, 3HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH |
| MS11 lgtE | 1,132.2 | 754.7 | 2,267.1 | 2,265.1 | 1.0 | Hex, HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH |
| MS11 lgtF | 1,051.1 | 2,104.2 | 2,102.9 | 1.0 | HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH | |
| 1291 | 1,679.1 | 1,119.2 | 3,360.4 | 3,361.1 | 1.0 | 4Hex, 4HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH |
| 1,578.3 | 1,051.7 | 3,158.1 | 3,157.9 | 0.8 | 4Hex, 3HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH | |
| 1,497.0 | 997.6 | 2,995.9 | 2,995.8 | 0.4 | 3Hex, 3HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH | |
| 1,396.3 | 930.5 | 2,794.5 | 2,792.6 | 0.4 | 3Hex, 2HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH | |
| 876.1 | 2,631.3 | 2,630.4 | 0.2 | 2Hex, 2HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH | ||
| 1291 lgtE | 1,132.1 | 754.7 | 2,266.6 | 2,265.1 | 1.0 | Hex, HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH |
| 1291 lgtF | 1,051.1 | 2,104.2 | 2,102.9 | 1.0 | HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH | |
| 1291 PorMS11 lgtE | 1,132.2 | 754.7 | 2,266.7 | 2,265.1 | 1.0 | Hex, HexNAc, 2Hep, 2Kdo, PEtn, lipid A-OH |
| FA19 | 1,457.8 | 971.5 | 2,917.5 | 2,995.8 | 1.0 | 3Hex, 2HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
| FA19 lgtE | 1,194.2 | 796.0 | 2,390.7 | 2,388.1 | 1.0 | Hex, HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
| FA19 lgtF | 1,112.6 | 741.6 | 2,227.5 | 2,226.0 | 1.0 | HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
| F62 | 1,457.7 | 971.6 | 2,917.6 | 2,915.6 | 1.0 | 3Hex, 2HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
| 1,559.2 | 1,039.3 | 3,120.6 | 3,118.8 | 0.6 | 3Hex, 3HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH | |
| F62 PorMS11 | 1,457.3 | 971.6 | 2,917.2 | 2,915.6 | 0.8 | 3Hex, 2HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
| 1,559.8 | 1,039.2 | 3,121.5 | 3,118.8 | 1.0 | 3Hex, 3HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH | |
| F62 PorMS11 lgtE | 1,194.1 | 795.7 | 2,390.1 | 2,388.1 | 1.0 | Hex, HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
| F62 PorMS11 lgtF | 1,113.1 | 741.6 | 2,228.0 | 2,226.0 | 1.0 | HexNAc, 2Hep, 2Kdo, 2PEtn, lipid A-OH |
The wild type and lgtE and lgtF mutants were examined for each strain, as indicated; in some cases, the porin from MS11 had replaced the host porin, as indicated. Additionally, for each strain/mutant, there is a consistent variation in the phosphorylation pattern of the lipid A-OH molecule, resulting in lipid A-OH molecules of 952, 1,075, 1,155, and 1,278, as is commonly observed in the pathogenic neisseriae. For simplicity, these “phosphoforms” are not detailed here.
Average mass units were used for calculation of molecular masses, based on proposed compositions, as follows: Sial, 291.00; Hex, 162.15; Hep, 192.17; HexNAc, 203.19; PEtn, 123.05; Kdo, 220.18. The average molecular mass of the O-deacylated lipid A (lipid A-OH) is as indicated.
Intensities are expressed as relative to the largest ions of the indicated charge states.