Effect of streptolysin O and digitonin on egg lecithin/cholesterol vesicles.
Effect of streptolysin O and digitonin on egg lecithin/cholesterol vesicles.
复制标题
链球菌溶血素 O 和洋地黄皂苷对鸡蛋卵磷脂/胆固醇囊泡的影响。
DOI：
10.1016/0005-2736(80)90414-9
复制
发表时间：
1980
期刊：
影响因子：
--
通讯作者：
A. Vistnes
中科院分区：
文献类型：
--
作者：
Evinar Rosenqvist;T. Michaelsen;A. Vistnes
人工膜囊泡（脂质体）已被用来研究细菌毒素，链球菌溶血素O的溶解机制，相比，众所周知的植物糖苷，毛地黄皂苷。制备了两种类型的囊泡：大单层囊泡和多层脂质体。用不同摩尔比的卵磷脂和胆固醇制备囊泡，并装载水溶性自旋标记物TEMPO-氯化胆碱。将囊泡的裂解登记为自旋标记的释放，并通过电子自旋共振（ESR）谱的变化进行监测。在该系统中，毛地黄皂苷能够裂解大的单层囊泡和多层脂质体。裂解的有效性通过增加胆固醇的百分比而增加，但即使在0%胆固醇下，通过添加足够大浓度的毛地黄皂苷也观察到显著水平的裂解。与此相反，没有裂解检测到暴露于链球菌溶血素O后，从多层脂质体，即使当它们由50摩尔%的胆固醇。另一方面，大的单层囊泡可以被链球菌溶血素O裂解，只要胆固醇含量大于33%。在膜中胆固醇为67mol%时，与50%相比，裂解程度降低，这似乎是最佳的。这是第一次证明脂质体溶解的链球菌溶血素O，并证明了胆固醇特异性，这已经显示了以前的抑制研究。
Artificial membrane vesicles (liposomes) have been used to study the lytic mechanism of the bacterial toxin, streptolysin O, compared to that of the well-known plant glycoside, digitonin. Two types of vesicle were prepared: large unilamellar vesicles and multilamellar liposomes. The vesicles were prepared with varying molar ratios of egg lecithin and cholesterol and loaded with the water-soluble spin label, TEMPO-choline chloride. Lysis of the vesicles was registered as release of spin label and monitored by change in the electron spin resonance (ESR) spectrum. In this system digitonin was able to lyse both large unilamellar vesicles and multilamellar liposomes. The effectiveness of lysis increased by increasing the percentage of cholesterol, but even at 0% cholesterol a significant level of lysis was observed by addition of a large enough concentration of digitonin. In contrast, no lysis was detected from multilamellar liposomes after exposure to streptolysin O, even when they consisted of 50 mol% cholesterol. On the other hand, large unilamellar vesicles could be lysed by streptolysin O, provided the cholesterol content was greater than 33%. At 67 mol% cholesterol in the membranes, the degree of lysis was diminished compared to 50%, which appeared to be optimal. This is the first demonstration of liposome lysis by streptolysin O and demonstrates the cholesterol specificity which has previously been shown by inhibition studies.