Mühlebach T, Cherry R J
Biochemistry. 1982 Aug 31;21(18):4225-8. doi: 10.1021/bi00261a006.
The cholesterol/phospholipid mole ratio (C/P) in the human erythrocyte membrane was varied by incubating cells with liposomes. The rotational mobility of band 3 proteins was measured in these membranes by observing flash-induced transient dichroism of the triplet probe eosin maleimide. Measurements were performed with membranes in which associations of band 3 with cytoskeletal proteins were removed by mild proteolysis with trypsin. It was found that decreasing C/P resulted in a more rapid decay of the flash-induced anisotropy. The anisotropy decay curves were analyzed by curve-fitting procedures, which indicated the existence of different sized small aggregates of band 3. The changes in the decay curves with varying C/P can be explained by an effect of cholesterol on the size distribution of these aggregates. The experiments suggest a possible role of cholesterol in regulating associations between integral membrane proteins.
通过将细胞与脂质体孵育，改变人红细胞膜中的胆固醇/磷脂摩尔比（C/P）。通过观察三联体探针马来酰亚胺曙红的闪光诱导瞬态二色性，测量这些膜中带3蛋白的旋转流动性。对用胰蛋白酶进行温和蛋白水解去除了带3与细胞骨架蛋白关联的膜进行测量。发现降低C/P会导致闪光诱导的各向异性更快衰减。通过曲线拟合程序分析各向异性衰减曲线，结果表明存在不同大小的带3小聚集体。随着C/P变化，衰减曲线的变化可以用胆固醇对这些聚集体大小分布的影响来解释。这些实验表明胆固醇在调节整合膜蛋白之间的关联中可能发挥作用。
