LPS structure comparison of E. coli strains W3110, HW001, HW002, WBB06, HWB01 and HWB02.

Red numbers specify the glucosamine ring positions, and the black numbers indicate the predominant fatty acid chain lengths. The enzymes WaaC, WaaF, LpxM and LpxE are shown in res with arrows indicating their functional domains, and the groups removed by these enzymes are shown in blue. Expression of lpxE in W3110 forms the strain HW001 that synthesizes PS-MPLA, and deletion of lpxM in HW001 forms the strain HW002 that synthesizes PS-pentaacyl-MPLA. Inactivation of waaC and waaF in W3110, HW001 and HW002 resulted in strains WBB06, HWB01 and HWB02, respectively. WBB06, HWB01, and HWB02 synthesize Kdo₂-lipid A, Kdo₂-MPLA and Kdo₂-pentaacyl-MPLA, respectively.