252Cf-plasma desorption mass spectrometry of unmodified lipid A: fragmentation patterns and localization of fatty acids.
The fragmentation patterns of synthetic Escherichia coli-type lipid A in plasma desorption mass spectrometry (PDMS) in both negative- and positive-ion modes were determined. Negative-ion spectra gave signals for the main diphosphorylated (intact) molecular species in their native proportions. Intact and alkaline-treated lipid A in this mode gave, for the glucosamine I moiety, easily identified signals that have not been previously reported in PDMS. These spectra gave enough information to localize the fatty acids. The procedure was verified with relatively homogeneous lipids A prepared from Salmonella minnesota R595 and Neisseria meningitidis lipopolysaccharides, and then applied to the previously unstudied Yersinia entercolitica O:11,24 lipid A to obtain the localization of its fatty acids. The possibility of obtaining this much information from two negative-ion spectra was attributed to the method, described earlier, of preparing the samples. In the positive-ion mode, about half of the E. coli ions containing diglucosamine appeared as monodephosphorylated species and/or as Na adducts. The intact glucosamine II moiety and its fragment ions gave signals none of which were Na adducts. With lipids A prepared from S. minnesota, N. meningitidis, and Y. enterocolitica, similar fragmentation patterns were observed. For lipid A structure determination, the positive-ion mode could play a confirmatory role. The above results and some of those reported by others were compared.
Karibian
D
D
Equipe 'Endotoxines', UMR 8619 du Centre National de la Recherche Scientifique, Biochimie, Université de Paris-Sud, F-91405 Orsay, France. doris.karibian@bbmpc.u-psud.fr
Brunelle
A
A
Aussel
L
L
Caroff
M
M
D004926:Escherichia coli / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis*; D005944:Glucosamine / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D008050:Lipid A / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000032:analysis; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D009345:Neisseria meningitidis / Q000737:chemistry; D012475:Salmonella / Q000737:chemistry; D055672:Static Electricity; D015008:Yersinia enterocolitica / Q000737:chemistry
D005227:Fatty Acids; D008050:Lipid A; D008070:Lipopolysaccharides; D005944:Glucosamine