Biosynthesis of glucosaminyl phosphatidylglycerol in .

Glucosaminyl phosphatidylglycerol (GlcN-PG) was first identified in bacteria in the 1960s and was recently reported in . Despite the important implications in altering membrane charge (by the modification of anionic PG with cationic glucosamine), the biosynthesis and functions of GlcN-PG have remained uncharacterized. Using bioinformatic and lipidomic analysis, we identified a 3-gene operon, renamed as , that is responsible for the biosynthesis and potential transport of GlcN-PG in : encodes a novel glycotransferase that is responsible for the modification of phosphatidylglycerol (PG) with -acetylglucosamine (GlcNAc) to produce GlcNAc-PG, and encodes a novel deacetylase that removes the acetyl group from GlcNAc-PG to produce GlcN-PG. The third gene in the operon, , is predicated to encode a flippase whose activity remains to be experimentally verified. As expected, the heterologous expression of the operon in resulted in production of both GlcNAc-PG and GlcN-PG. The identification of the biosynthetic genes of GlcN-PG paves the way for the investigation of its biological and pathological functions, which has significant implications in our understanding of the unique membrane physiology, pathogenesis and antimicrobial resistance of .