FIGURE 1.

General structure of LPS from E. coli. The lipid A part is composed of a di‐glucosamide backbone with two phosphoryl groups and up to four fatty acid chains. It is the lipid A part of LPS which is responsible for the endotoxic activity. The carbohydrate part is divided into a core polysaccharide part and a so‐called O‐antigen. The core polysaccharide consists of a conserved inner core containing unusual sugars, mainly 2 keto‐3‐deoxyoctonate (Kdo) and heptose (Hep). The outer core is made of common hexoses such as glucose (Glu) and galactose (Gal). The core oligosaccharide can be further modified, for example, phosphorylated. The O‐antigen is a polysaccharide composed of a variable number of repeating oligosaccharide building blocks and is in general highly diverse