Figure 3.

Electrospray MS of PE DHC lipids recovered from P. gingivalis. Total lipids of P. gingivalis were isolated and fractionated by HPLC as described in Material and Methods. Fractions containing the characteristic molecular ions of PE DHC lipids were pooled and repurified by HPLC. Repurified fractions demonstrating 705, 699, and 677 negative ions were pooled. The structure of the high-mass PE DHC lipid (705 m/z) is shown in the inset with the component fatty acid and long-chain base structures identified. The lower-mass PE DHC lipids indicated by 691 or 677 m/z ions contain 18 carbon or 17 carbon long-chain bases, respectively, as previously described.4 Note the absence of ions characteristic for lipid A moieties produced by P. gingivalis (1195, 1435, 1449, 1690, and 1770 m/z negative ions).