TABLE 2.
Negative-ion nES-MS data and proposed compositions of O-deacylated LOSs from H. somnus 738, knockout mutant 738-lob2A1::Km, strain 129Pt, and recombinant strain 129Pt(pLSlob2A)
| Strain | Observed ions (m/z)
|
Molecular mass (Da)a
|
Relative intensity (fold)b | Proposed compositionc | ||
|---|---|---|---|---|---|---|
| (M-2H)2− | (M-H)3− | Observed | Calculated | |||
| 738 | 1,111.1 | 740.3 | 2,224.0 | 2,224.1 | 0.2 | 2Hex, 2Hep, PEtn, 2Kdo, lipidA |
| 1,192.0 | 794.4 | 2,386.0 | 2,386.2 | 0.2 | 3Hex, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,194.0 | 795.2 | 2,389.0 | 2,389.1 | 0.2 | 2Hex, 2Hep, PEtn, PCho, 2Kdo, lipid A | |
| 1,294.0 | 862.8 | 2,590.0 | 2,589.4 | 1.0 | HexNAc, 3Hex, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,375.0 | 916.1 | 2,752.0 | 2,751.6 | 0.5 | HexNAc, 4Hex, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,458.0 | 971.3 | 2,917.0 | 2,916.7 | 0.3 | HexNAc, 4Hex, 2Hep, PEtn, PCho, 2Kdo, lipid A | |
| 738-lob2A1::Km | 1,111.0 | 740.3 | 2,224.0 | 2,224.1 | 0.7 | 2Hex, 2Hep, PEtn, 2 Kdo, lipid A |
| 1,192.0 | 794.3 | 2,386.0 | 2,386.2 | 1.0 | 3Hex, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,273.0 | 848.3 | 2,548.0 | 2,548.4 | 0.3 | 4Hex, 2Hep, PEtn, 2Kdo, lipidA | |
| 129Pt | 1,131.6 | 2,265.0 | 2,265.1 | 0.75 | Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,212.8 | 2,427.0 | 2,427.2 | 0.20 | 2Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,293.7 | 2,589.0 | 2,589.4 | 1.00 | 3Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 129Pt(pLSlob2A) | ||||||
| Analysis 1 | 1,131.7 | 2,265.0 | 2,265.1 | 0.40 | Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,172.1 | 2,345.0 | 2,345.1 | 0.40 | Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A, P | ||
| 1,212.5 | 2,427.0 | 2,427.2 | 0.10 | 2Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,293.6 | 2,589.0 | 2,589.4 | 1.00 | 3Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,314.1 | 2,630.0 | 2,630.4 | 1.10 | 2Hex, 2HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,333.4 | 2,669.0 | 2,669.4 | 0.90 | 3Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,354.2 | 2,710.0 | 2,710.4 | 1.25 | 2Hex, 2HexNAc, 2Hep, PEtn, 2Kdo, lipid A, P | ||
| Analysis 2 | 1,131.7 | 2,265.0 | 2,265.1 | 0.50 | Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | |
| 1,172.1 | 2,345.0 | 2,345.1 | 0.05 | Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A, P | ||
| 1,212.5 | 2,427.0 | 2,427.2 | 0.15 | 2Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,293.8 | 2,589.0 | 2,589.4 | 1.00 | 3Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,314.1 | 2,630.0 | 2,630.4 | 0.70 | 2Hex, 2HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,334.0 | 2,669.0 | 2,669.4 | 0.20 | 3Hex, HexNAc, 2Hep, PEtn, 2Kdo, lipid A | ||
| 1,353.6 | 2,710.0 | 2,710.4 | 0.20 | 2Hex, 2HexNAc, 2Hep, PEtn, 2Kdo, lipid A, P | ||
a
Average mass units were used for calculation of molecular weight based on the proposed composition as follows: Hex, 162.15; Hep, 192.17; HexNAc, 203.19; Kdo, 220.18; PEtn, 123.05. PCho, 165.05, lipid A, 953.01.
b
Relative intensity is expressed with respect to the most intense peak of the doubly charged ions in the spectrum.
c
Abbreviations: Hep, heptose; PEtn, phosphoethanolamine; PCho, phosphorylcholine; Kdo, 3-deoxy-d-manno-2-octulosonic acid; P, phosphate.