title: Isolation and characterization of 2-keto-3-deoxyoctonate-lipid A from a heptose-deficient mutant of Escherichia coli.
abstract: A heptose-deficient mutant of Escherichia coli has been isolated and from it a glycolipid, consisting of lipid A and 2-keto-3-deoxyoctonate (KDO), has been extracted with diisobutylketone-acetic acid-water. Based on beta-hydroxymyristic acid, the extractable glycolipid accounts for a major portion of the total lipid A in this mutant. A glycolipid, purified from the lipid extract by a combination of silicic acid and Sephadex LH-60 chromatography, contains glucosamine, phosphate, KDO, acetyl groups, and fatty acids in the following molar ratios: 1:2:2:1.7:5. These components account for over 80% of the lipid by weight. The fatty acid pattern of the glycolipid is typical of lipid A, the major component being beta-hydroxymyristic acid. The lipid also contains an amino sugar which appears to be 4-amino-4-deoxyarabinose. With the use of an ion-exchange paper chromatographic technique, gram-negative bacteria can be rapidly screened for the presence of this glycolipid. The mutant is believed to have a leaky defect in either biosynthesis of heptose or its incorporation into lipopolysaccharide. The lipopolysaccharide from the mutant contains only about a third as much heptose, glucose, and galactose as the parent CR34, a K-12 derivative. Chemical analysis and phage typing suggest that CR34 contains an incomplete core polysaccharide devoid of glucosamine.
mesh_terms: D001345:Autoradiography; D001434:Bacteriophage Typing; D002210:Caprylates / Q000032:analysis; D002473:Cell Wall / Q000032:analysis; D002854:Chromatography, Paper; D002855:Chromatography, Thin Layer; D004590:Electrophoresis, Paper; D004926:Escherichia coli / Q000032:analysis* / Q000378:metabolism; D005227:Fatty Acids / Q000032:analysis; D005827:Genetics, Microbial; D005944:Glucosamine; D006017:Glycolipids / Q000032:analysis* / Q000302:isolation & purification; D006539:Heptoses / Q000032:analysis / Q000378:metabolism; D006601:Hexoses / Q000032:analysis; D007659:Ketones / Q000032:analysis; D008070:Lipopolysaccharides / Q000032:analysis; D009154:Mutation; D010743:Phospholipids / Q000032:analysis; D010759:Phosphorus Isotopes; D011135:Polysaccharides, Bacterial / Q000032:analysis; D012997:Solvents
chemical_list: D002210:Caprylates; D005227:Fatty Acids; D006017:Glycolipids; D006539:Heptoses; D006601:Hexoses; D007659:Ketones; D008070:Lipopolysaccharides; D010743:Phospholipids; D010759:Phosphorus Isotopes; D011135:Polysaccharides, Bacterial; D012997:Solvents; D005944:Glucosamine