Jones N C, Osborn M J
J Biol Chem. 1977 Oct 25;252(20):7405-12.
The reversibility and specificity of phospholipid translocation between the inner and outer membrane of Salmonella typhimurium has been investigated by incorporating exogenous lipids from phospholipid vesicles into the outer membrane of intact cells. Translocation of newly incorporated phospholipids to the inner membrane was demonstrated by decarboxylation of vesicle-derived phosphatidylserine and by recovery of vesicle constituents in both inner and outer membrane fractions. All Salmonella phospholipids tested, as well as phosphatidylcholine and cholesteryl oleate were effectively translocated to the inner membrane. However, no translocation of vesicle-derived lipopolysaccharide or an incomplete biosynthetic precursor of lipid A could be detected. Translocation of phospholipids and cholesteryl ester was rapid and extensive, and appeared to lead to equilibration of the lipids between the two membranes. The mechanism of intermembrane translocation has not been established, but the results are suggestive of diffusional flow across zones of adhesion between the inner and outer membranes.
通过将磷脂囊泡中的外源脂质掺入完整细胞的外膜，研究了鼠伤寒沙门氏菌内膜和外膜之间磷脂转运的可逆性和特异性。通过对囊泡衍生的磷脂酰丝氨酸进行脱羧以及在内膜和外膜组分中回收囊泡成分，证明了新掺入的磷脂向内膜的转运。所有测试的沙门氏菌磷脂以及磷脂酰胆碱和胆固醇油酸酯都有效地转运到了内膜。然而，未检测到囊泡衍生的脂多糖或脂质A的不完全生物合成前体的转运。磷脂和胆固醇酯的转运迅速且广泛，似乎导致了脂质在两个膜之间的平衡。膜间转运的机制尚未确定，但结果提示跨内膜和外膜之间粘附区域的扩散流动。
