Miyazaki C, Kuroda M, Ohta A, Shibuya I
Proc Natl Acad Sci U S A. 1985 Nov;82(22):7530-4. doi: 10.1073/pnas.82.22.7530.
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.
从在非允许温度下培养的温度敏感型菌株中分离出了大肠杆菌K-12的独特突变体，这些突变体在磷脂酰甘油合成方面存在缺陷。亲本菌株通过同时携带pss-1等位基因[编码温度敏感型磷脂酰丝氨酸合酶（EC 2.7.8.8）]和cls-等位基因（导致心磷脂合酶缺陷）而含有过量的磷脂酰甘油。新获得的突变在较高温度下能促进更好的生长。其中一个突变（pgsA3）已在磷脂酰甘油磷酸合酶[甘油磷酸磷脂酰转移酶（EC 2.7.8.5）]的结构基因中被鉴定出来。这些突变体的磷脂组成很显著；磷脂酰乙醇胺是唯一的主要脂质。在低渗透压培养基中，这些细胞的生长比野生型细胞更慢。在适当添加蔗糖和MgCl2的培养基中，它们能正常生长，而不会从磷脂异常中恢复。在pgsA3突变体中，心磷脂和膜衍生寡糖的磷酸甘油衍生物的形成减少。单独或组合具有pgsA3、pss-1和cls-突变的大肠杆菌菌株构成了一个经验系统，在这个系统中，三种主要膜磷脂的摩尔比可以被不同地改变。
