Architecture of bacterial lipid A in solution. A neutron small-angle scattering study.
The phase structure of isolated bacterial lipid A, the lipid anchor of the lipopolysaccharides of the outer membrane of Gram-negative bacteria, has been investigated by neutron small-angle scattering. The shape of the scattering curves obtained at different H2O/2H2O ratios revealed a lamellar organisation of the lipid A at neutral pH both above and below its main phase temperature (approximately 40-45 degrees C). Analysis of the scattering curves and interpretation of the corresponding thickness distance distribution functions of the lamellar aggregates led to a model in which the lipid A molecules form a bilayer of about 5 nm in thickness. This value for the thickness of the bilayer, as well as the neutron-scattering density profile across the bilayer, can be explained by a molecular model which shows interdigitation of the fatty acid chains of the lipid A.
Labischinski
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Robert Koch-Institut des Bundesgesundheitsamtes, Berlin.
Vorgel
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Uebach
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May
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RP
Bradaczek
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H
D006863:Hydrogen-Ion Concentration; D008050:Lipid A / Q000032:analysis*; D008051:Lipid Bilayers / Q000032:analysis; D008070:Lipopolysaccharides / Q000032:analysis; D008854:Microscopy, Electron; D008958:Models, Molecular; D015394:Molecular Structure; D009502:Neutrons; D012475:Salmonella / Q000032:analysis*; D012542:Scattering, Radiation; D012996:Solutions; D013696:Temperature
D008050:Lipid A; D008051:Lipid Bilayers; D008070:Lipopolysaccharides; D012996:Solutions