Incorporation of acyl moieties of phospholipids into murein lipoprotein in intact cells of Escherichia coli by phospholipid vesicle fusion.

The biosynthesis of the acyl moieties in murein lipoprotein was studied by fusion of [3H]palmitate-labeled phospholipid vesicles with intact cells of an fadD mutant of Escherichia coli. A linear increase in the incorporation of [3H]palmitate radioactivity into both the ester- and amide-linked fatty acids in lipoprotein was observed during a 3-h chase after the fusion. Addition of chloramphenicol completely prevented the incorporation of [3H]palmitate from phospholipids to lipoprotein. These results strongly support our hypothesis that the acyl moieties in phospholipids are the precursors for the fatty acids in murein lipoprotein of E. coli. Among the major glycerophosphatides in E. coli, no specificity was observed regarding the efficacy of the donor.