There are several lipid A forms in this strain, including a phosphoethanolamine (1-O-P-pEtN) form; overexpression of this gene leads to higher levels of the 1-O-P-pEtN form of lipid A. Decreased amounts of the 1-O-P-PEtN form of lipid A. Belongs to the phosphoethanolamine transferase family. EptA subfamily.