has disposition attached to lipid As lipid A http://purl.obolibrary.org/obo/chebi.owl The glycolipid moiety of bacterial lipopolysaccharide (R can be either hydrogen or a fatty acyl group). Lipid A is the component of the lipopolysaccharide portion of the outer membrane of gram-negative bacteria which is responsible for its endotoxicity. When lipid A enters the circulatory system it causes a toxic reaction by activating toll like receptor TLR 4. (BIDO axiom editor) Shane Babcock oligosaccharide virulence factor disposition toxin disposition endotoxin disposition