Selection and characterization of an E. coli mutant defective in membrane lipid biosynthesis

A procedure is described for the selection of temperature-sensitive phospholipid mutants based upon radiation suicide of the wild-type organisms by tritiated L-glycerol-3-phosphate incorporated in the phospholipids. One of these mutants possesses an acyltransferase activity much more thermolabile than that of its parent. This mutant ceases growth and phospholipid biosynthesis immediately upon shift to a nonpermissive temperature although DNA, RNA, and protein continue to be synthesized. The phenotype of this mutant appears due to a single mutation by reversion analysis and by enzymatic analysis of temperature-resistant revertants.