title: Metabolism of the phosphatidylglycerol molecular species in Escherichia coli.
abstract: The fractionation, turnover and biosynthesis of the phosphatidylglycerol molecular species of Escherichia coli were studied. Monoacetyldiglycerides derived from phosphatidylglycerol were separated into five subfractions; cis-vaccenyl-palmitoleyl, cis-vaccenyl-cis-vaccenyl, palmityl-palmitoleyl, palmityl-cis-vaccenyl and the disaturated molecular species on a silica gel plate impregnated with silver nitrate. Individual molecular species had different turnover rates. The palmityl-cis-vaccenyl species was metabolized faster than the others. Disaturated species were rather stable. Various phosphatidylglycerol molecular species were synthesized in the presence of sn-glycerol 3-phosphate, palmityl-CoA, palmitoleyl-CoA, cis-vaccenyl-CoA and CTP by the E. coli membrane particulate fraction. When only the proportion of palmityl-CoA among the three acyl-CoAs was increased, the molecular species containing the palmityl residue were increased. Similar results were obtained with the other acyl-CoAs. However, a temperature-sensitive incorporation of unsaturated and saturated fatty acids into phosphatidylglycerol molecular species was observed with no change in the proportions of the three acyl-CoAs, completely reflecting the in vivo unsaturated/saturated ratio.
mesh_terms: D002250:Carbon Radioisotopes; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D002499:Centrifugation, Density Gradient; D002855:Chromatography, Thin Layer; D004926:Escherichia coli / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D005992:Glycerol-3-Phosphate O-Acyltransferase / Q000032:analysis; D007553:Isotope Labeling; D013058:Mass Spectrometry; D010714:Phosphatidylethanolamines / Q000378:metabolism; D010715:Phosphatidylglycerols / Q000032:analysis / Q000096:biosynthesis / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D013696:Temperature; D013997:Time Factors; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D010743:Phospholipids; D014316:Tritium; D005992:Glycerol-3-Phosphate O-Acyltransferase