Table 1.

Summary of MALDI-TOF MS observations and predicted masses of ions and fragments.

Molecule	[M − H]− Predicted Mass (Da)	[M − H]− Observed m/z	B1+ Predicted Mass (Da)	B1+ Observed m/z	B2+ Predicted Mass (Da)	B2+ Observed m/z	[M + Na]+ Predicted Mass (Da)	[M + Na]+ Observed m/z
E. coli hexa-acyl	1797.36	1797.30	1087.51	1087.63	1701.38	1701.25	1821.35	1821.74
P. marina penta-acyl	1611.02	1611.21	901.21	900.94	1515.04	1514.01	1635.02	1634.20
hexa-acyl	1793.33	1793.45	1083.48	1083.31	1697.35	1696.23	1817.32	1816.42
A. baumannii hexa-acyl	1730.20	1729.77	1047.40	1047.78	1633.22	1633.17	1753.19	1753.21
hexa-acyl − (OH)	1714.21	1713.80	1031.41	1031.90	1617.22	1616.93	1737.20	1737.31
hexa-acyl − (CH2)2	1702.15	1701.71	1019.35	1019.68	1605.16	1604.72	1725.14	1724.97
hepta-acyl	1911.50	1911.92	1047.40	1047.78	1815.52	1815.27	1935.50	1935.53
hepta-acyl − (OH)	1895.50	1896.18	1031.41	1031.90	1799.52	--	1919.50	1920.34
hepta-acyl − (CH2)2	1883.45	1883.93	1019.35	1019.68	1787.47	1787.30	1907.44	1907.36
P. cryohalolentis − (CH2)3	1558.91	1558.96	905.17	907.11	1462.93	1461.39	1582.90	1581.95
−(CH2)2	1572.93	1573.14	919.19	919.09	1476.95	1476.26	1596.93	1596.22
−CH2	1586.96	1587.15	933.22	934.13	1490.98	1489.93	1610.96	1610.55
hexa-acyl	1600.98	1601.16	947.25	947.07	1505.01	1504.06	1624.98	1624.52
+CH2	1615.01	1615.23	961.27	961.36	1519.03	1517.92	1639.01	1638.86
+(CH2)2	1629.04	1629.23	975.30	975.01	1533.06	1532.13	1653.04	1652.71
+(CH2)3	1643.06	1643.30	989.33	990.63	1547.09	1546.00	1667.06	1667.18
+(CH2)4	1657.09	1657.13	1003.35	1003.68	1561.11	--	1681.09	1680.35

Calibrated mass/charge ratios (observed mass) of major ions in the MALDI-TOF MS spectra (Figure 1, Figure 2, Figure 3 and Figure 4) are compared to the calculated molecular weight (predicted mass) of each ion based on the proposed lipid A structures. See Figure 6 for proposed structures and Figure 1 for structural definitions. [--] = not detected.