Which component gives Gram-negative bacteria endotoxic properties?
The outer leaflet of Gram-negative outer membrane is dominated by lipopolysaccharide, a high-molecular-weight amphipathic complex consisting of variable O-antigen polysaccharide, conserved core oligosaccharide containing 3-deoxy-D-manno-octulosonate (Kdo), and hydrophobic lipid A anchor. Lipid A is the endotoxic principle. Chemically it is a beta-1,6-linked D-glucosamine disaccharide phosphorylated at positions 1 and 4 prime and hexa-acylated with 3-hydroxy fatty acids in Escherichia coli, a structure absent from mammalian membranes. This moiety serves as a classic pathogen-associated molecula
Ref: Raetz & Whitfield, Ann Rev Biochem 2002, LPS Endotoxins; Janeway's Immunobiology, 9th ed., Recognition of LPS.
