Endotoxin of Neisseria meningitidis composed only of intact lipid A: inactivation of the meningococcal 3-deoxy-D-manno-octulosonic acid transferase.
Lipopolysaccharide, lipooligosaccharide (LOS), or endotoxin is important in bacterial survival and the pathogenesis of gram-negative bacteria. A necessary step in endotoxin biosynthesis is 3-deoxy-D-manno-octulosonic acid (Kdo) glycosylation of lipid A, catalyzed by the Kdo transferase KdtA (WaaA). In enteric gram-negative bacteria, this step is essential for survival. A nonpolar kdtA::aphA-3 mutation was created in Neisseria meningitidis via allelic exchange, and the mutant was viable. Detailed structural analysis demonstrated that the endotoxin of the kdtA::aphA-3 mutant was composed of fully acylated lipid A with variable phosphorylation but without Kdo glycosylation. In contrast to what happens in other gram-negative bacteria, tetra-acylated lipid IV(A) did not accumulate. The LOS structure of the kdtA::aphA-3 mutant was restored to the wild-type structure by complementation with kdtA from N. meningitidis or Escherichia coli. The expression of a fully acylated, unglycosylated lipid A indicates that lipid A biosynthesis in N. meningitidis can proceed without the addition of Kdo and that KdtA is not essential for survival of the meningococcus.
Tzeng
Yih-Ling
YL
Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30303, USA.
Datta
Anup
A
Kolli
V Kumar
VK
Carlson
Russell W
RW
Stephens
David S
DS
D000483:Alleles; D004591:Electrophoresis, Polyacrylamide Gel; D019286:Endopeptidase K; D005816:Genetic Complementation Test; D005822:Genetic Vectors; D005838:Genotype; D008050:Lipid A / Q000032:analysis* / Q000096:biosynthesis / Q000737:chemistry; D008070:Lipopolysaccharides / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D015394:Molecular Structure; D009154:Mutation; D009345:Neisseria meningitidis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013400:Sugar Acids / Q000032:analysis; D014166:Transferases / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics
D008050:Lipid A; D008070:Lipopolysaccharides; D013400:Sugar Acids; C023023:lipid-linked oligosaccharides; C002532:2-keto-3-deoxyoctonate; D014166:Transferases; C019917:3-deoxy-D-manno-octulosonate transferase; D019286:Endopeptidase K