FIGURE 5.

ESI FT-ICR mass spectra in negative ion mode of LPS isolated from waaA deletion grown in LB medium at 30 °C (A) and 21 °C in LB medium (B), in M9 medium (C), and 121 medium (D). The left inset shows in detailed part of the spectra containing tetraacylated lipid IV_A precursor. Mass numbers correspond to (M − H⁺)⁻ ions. Addition of lauroyl, myristoyl, palmitoleate, palmitoyl, and P-EtN moieties to lipid IV_A precursor and their derivatives are drawn schematically. These spectra also contain intensive signals for phospholipids. The ion peak at m/z 1404.0 in the inset could correspond to either phospholipid dimmer or a cardiolipin.