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. Author manuscript; available in PMC: 2015 Aug 1.
Published in final edited form as: Biochim Biophys Acta. 2013 Dec 14;1843(8):1475–1488. doi: 10.1016/j.bbamcr.2013.12.007

Fig. 2.

Fig. 2

Manipulating membrane phospholipid composition in vivo using E. coli. (A) Pathways native to E. coli are noted with blue arrows, and pathways resulting from foreign genes introduced into E. coli are noted with red arrows [50]. Lipids are color coded as zwitterionic (blue), neutral (green), anionic (orange) or cationic (gray). The genes encoding the following enzymes and associated with each biosynthetic step are listed next to the arrows: (1) CDP-diacylglycerol synthase; (2) PS synthase; (3) PS decarboxylase; (4) PGP synthase; (5) PGP phos-phatases; (6) CL synthases; (7) PG: membrane derived oligosaccharide sn-glycerol-1-P transferase; (8) diacylglycerol kinase; (9) GlcDAG synthase (Acholeplasma laidlawii); (10) GlcGlcDAG synthase (A. laidlawii); (11) PC synthase (Legionella pneumophila); (12) PI synthase (Saccharomyces cerevisiae); (13) N-Acyl PE synthase; (14) O-Acyl PG synthase; and (15) O-Lysyl PG synthase (Staphylococcus aureus) utilizing Lysyl-tRNA as the lysine donor. (B) Lipid profiles displayed by thin layer chromatography of 32PO4-labeled E. coli mutants with altered lipid compositions. Lane 1. AL95 (ΔpssA) has wild type phospholipid composition (80 mol% PE and 20 mol% PG plus CL) due to complementation by a plasmid (pDD72) copy of the pssA gene that encodes the committed step to PE biosynthesis. Lane 2. AL95 is PE-lacking due to the null allele of the pssA gene and contains mainly CL and PG. Lane 3. Introduction of the mgs gene from A. laidlawii into strain AL95 results in 35 mol% GlcDAG. The remaining lipids are primarily PG (35 mol%) and CL (25 mol%). Lane 4. Introduction into AL95 of the mgs and dgs genes from A. laidlawii results in about 30–40 mol% GlcGlcDAG with less than 1 mol% GlcDAG. Lane 5. Introduction into AL95 of the pcs gene from L. pneumophila results in about 70 mol% PC with the remainder being PG (26 mol%) plus CL (2.5 mol%). Lane 6. UE54 carries a null allele of the pgsA gene encoding the committed step to PG and CL biosynthesis making it devoid of PG and CL and containing about 90 mol% PE, 4 mol% PA and 3.2 mol% CDP-diacylglycerol. Lane 7. Introduction into AL95 of the mprF gene from S. aureus results in about 60 mol% of O-Lysyl-PG (LPG) with the remainder being PG (9 mol%) plus CL (30 mol%) and other minor lipids. Lane 8. Introduction of the mprF gene into “wild-type” AL95/pDD72 results in about 23 mol% of LPG, 44 mol% of PE, 11 mol% of PG and 22 mol% of CL.