Structural studies of lipid A from Pseudomonas aeruginosa PAO1: occurrence of 4-amino-4-deoxyarabinose.
Lipid A derived from Pseudomonas aeruginosa PAO1 contains a biphosphorylated 1-6-linked glucosamine disaccharide backbone. The reducing glucosamine has an unsubstituted glycosidically linked phosphate at C-1. The nonreducing glucosamine has an ester-bound phosphate at C-4' which is nonstoichiometrically substituted with 4-amino-4-deoxyarabinose. Induction of 4-amino-4-deoxyarabinose was dependent on cultural conditions. No pyrophosphate groups were detected. Acyloxyacyl diesters are formed by esterification of the amide-bound 3-hydroxydodecanoic acid with dodecanoic acid and 2-hydroxydodecanoic acids in an approximate molar ratio of 2:1. Dodecanoic and 3-hydroxydecanoic acids are esterified to positions C-3 and C-3' in the sugar backbone. All hydroxyl groups of the glucosamine disaccharide except C-4 and C-6' are substituted. Lipopolysaccharide chemical analyses measured glucose, rhamnose, heptose, galactosamine, alanine, phosphate, and glucosamine. The proposed lipid A structure differs from previous models. There are significant differences in acyloxyacyl diesters, and the proposed model includes an aminopentose substituent.
Bhat
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Max-Planck-Institut für Immunbiologie, Freiburg-Zähringen, Federal Republic of Germany.
Marx
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Galanos
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Conrad
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D000606:Amino Sugars / Q000032:analysis*; D001089:Arabinose / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D008050:Lipid A / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011550:Pseudomonas aeruginosa / Q000032:analysis*
D000606:Amino Sugars; D005227:Fatty Acids; D008050:Lipid A; D008070:Lipopolysaccharides; C040134:4-amino-4-deoxyarabinose; D001089:Arabinose