Genetic manipulation of membrane phospholipid composition in Escherichia coli: pgsA mutants defective in phosphatidylglycerol synthesis.
Unique mutants of Escherichia coli K-12, defective in phosphatidylglycerol synthesis, have been isolated from a temperature-sensitive strain incubated at its nonpermissive temperature. The parent strain had excess phosphatidylglycerol by harboring both the pss-1 allele [coding for a temperature-sensitive phosphatidylserine synthase (EC 2.7.8.8)] and the cls- allele (responsible for a defective cardiolipin synthase). The newly acquired mutations caused better growth at higher temperatures. One of the mutations (pgsA3) has been identified in the structural gene for phosphatidylglycerophosphate synthase [glycerophosphate phosphatidyltransferase (EC 2.7.8.5)]. Phospholipid compositions of these mutants were remarkable; phosphatidylethanolamine was the sole major lipid. In media with low osmotic pressures, these cells grew more slowly than the wild-type cells. They grew normally without recovering from the phospholipid abnormality in media appropriately supplemented with sucrose and MgCl2. Formation of cardiolipin and phosphoglycerol derivatives of membrane-derived oligosaccharides was reduced in a pgsA3 mutant. E. coli strains having the pgsA3, pss-1, and cls- mutations, either individually or in combination, constitute an empirical system in which the molar ratio of three major membrane phospholipids can be variously altered.
D002308:Cardiolipins / Q000096:biosynthesis; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial; D008563:Membrane Lipids / Q000032:analysis*; D009154:Mutation; D010715:Phosphatidylglycerols / Q000096:biosynthesis*; D010743:Phospholipids / Q000032:analysis* / Q000096:biosynthesis; D010770:Phosphotransferases / Q000235:genetics*; D017855:Transferases (Other Substituted Phosphate Groups)
D002308:Cardiolipins; D008563:Membrane Lipids; D010715:Phosphatidylglycerols; D010743:Phospholipids; D010770:Phosphotransferases; D017855:Transferases (Other Substituted Phosphate Groups); C020676:CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase