Temperature-sensitive formation of the phospholipid molecular species in Escherichia coli membranes.

Phospholipids in the membranes of Escherichia coli grown at 37 degrees C are composed of different proportions of molecular species than are those at 17 degrees C. The 1,2-disaturated and 1-saturated-2-unsaturated molecular species increased at 37 degrees C, but the 1,2-diunsaturated species increased at 17 degrees C. When the growth temperature was lowered from 37 to 17 degrees C during the middle exponential growth phase, phosphatidylethanolamine and phosphatidylglycerol composed of proportions of molecular species similar to those found at 17 degrees C were immediately synthesized. By using various membranes composed of different compositions of the phospholipid molecular species, the temperature-sensitive formation of the phospholipid molecular species was found to be independent of the composition of the membrane phospholipids and to be dependent on changes in the specificities of membrane-bound sn-glycerol 3-phosphate acyltransferase against the acyl-CoAs, due to temperature changes.