Comparison of the chemical structure of lipopolysaccharide from E. coli serotype O111 and the phospholipid DOPC (1,2-dioleoyl-sn-glycero-3-phosphocholine). Partial covalent modifications, which may result in additional phosphate groups, are shown (dotted lines) and are dependent on growth conditions and other factors. Number of repeat units in the O-chain, n, ranges from 1 to 18. COL, colitose (3,6-dideoxy-L-xylo-hexose); GAL, galactopyranose; GLC, glucopyranose; GLCN, 2-amino-2-deoxyglucopyranose; HEP, L-glycero-D-manno-heptopyranose; KDO, 3-deoxy-D-manno-oct-2-ulopyranosonic acid; P, phosphate.