FIG 5.

The ΔPGN_1123 mutant is devoid of tetra-acylated lipid A. (A) Lipid A preparations of ΔPGN_1123::ermF mutants exhibit penta-acylated nonphosphorylated lipid A as detected by MALDI-TOF MS in positive-ion mode and a distinct absence of tetra-acylated lipid A. (B) ΔPGN_1123 mutants expressing the PGN_1123 gene in trans from pSJ836 display tetra-acylated nonphosphorylated lipid A, similar to that of the wild type, indicating complementation of lipid A deacylase function. Numbers refer to the m/z ratio of the predominant peak in each lipid A cluster.