Figure 25-40. Structure of lipopolysaccharide (LPS).

Figure 25-40Structure of lipopolysaccharide (LPS)

On the left is the 3-dimensional structure of a molecule of LPS with the fatty acids shown in yellow and the sugars in blue. The molecular structure of the base of LPS is shown on the right. The hydrophobic membrane anchor is made up of two linked glucosamine sugars attached to three phosphates and six fatty acid tails. This basic structure is elaborated by attachment of a long, usually highly branched, chain of sugars. This drawing shows the simplest type of LPS that will allow E. coli to live; it has just two sugar molecules in the chain, both 3-deoxy-D-manno-octulosonic acid. At the position marked by the arrow, wild-type Gram-negative bacteria also attach a core saccharide made up of eight to twelve linked sugars and a long O antigen, which is made up of an oligosaccharide unit that is repeated many (up to 40) times. The sugars making up the core saccharide and O antigen vary from one bacterial species to another and even among different strains of the same species. All forms of LPS are highly immunogenic.

From: Innate Immunity

Cover of Molecular Biology of the Cell
Molecular Biology of the Cell. 4th edition.
Alberts B, Johnson A, Lewis J, et al.
New York: Garland Science; 2002.
Copyright © 2002, Bruce Alberts, Alexander Johnson, Julian Lewis, Martin Raff, Keith Roberts, and Peter Walter; Copyright © 1983, 1989, 1994, Bruce Alberts, Dennis Bray, Julian Lewis, Martin Raff, Keith Roberts, and James D. Watson .

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