FIG. 3.
Comparison of the lipid A fractions isolated from wild-type H. pylori and lpxEHP mutants. Lipids A of the indicated strains were analyzed by MALDI-TOF mass spectrometry in the negative-ion mode. Although mass spectrometry data was acquired on lipids eluting in each fraction from the DEAE column (40), only those fractions containing lipids are shown. Lipid I from wild-type strains 26695 (A) and J99 (D) were found to elute in the flowthrough and wash fractions, whereas lipid II (B, E, and F) produced by lpxEHP mutants eluted in the 120 mM salt fraction (see Materials and Methods). Lipid III (C), produced only by the 26695/lpxEHP::cm mutant, eluted in the 240 mΜ salt fraction.