Schematic diagram of the general structure of lipopolysaccharides of Gram neg-ative bacteria. Lipolysaccharides of Gram negative bacteria consist of three mainsubunits (from bottom to top): lipid A, the core region and the O-antigen. Lipid Aand the core-region form rough (R)-type LPS. Lipid A, the core-region and the O-antigen together form smooth (S)-type LPS. The number and chemical structureof the acyl chains can vary. Sugar moieties are depticted as hexagons in differentcolours. The number and chemical structure of these sugar moieties can vary.