Structural modification of Escherichia coli lipid A by myristoyltransferase gene from Klebsiella pneumoniae

Lipid A in lipopolysaccharide (LPS) of Escherichia coli mutant strains was modified by the introduction of myristoyltransferase gene cloned from Klebsiella pneumoniae. When the gene was introduced into the mutant having lipid A containing only 3‐hydroxymyristic acids, it produced lipid A with two additional myristic acids (C_14:0). When the same gene was introduced into the mutant with pentaacylated lipid A containing one lauric acid (C_12:0), C_12:0 was replaced by C_14:0. IL‐6‐inducing activity of LPS with modified lipid A structure suggested that C_12:0 in lipid A could be replaced by C_14:0 without changing the immunostimulating activity.