Cherry R J
Biochem Soc Symp. 1981(46):183-90.
Rotational diffusion of membrane proteins may be measured by detecting flash-induced transient dichroism of triplet probes or intrinsic chromophores. The method is illustrated by the following applications. 1. Anisotropy decay curves have been measured for bacteriorhodopsin incorporated into lipid vesicles. The data are used to critically test a theoretical model in which it is assumed that protein rotation occurs only around the membrane normal. 2. Rotational diffusion of eosin-labelled band-3 proteins in the human erythrocyte membrane has been investigated. The measurements illustrate the value of protein rotation measurements for studying protein-protein associations in membranes. In particular, it is shown that up to 40% of band-3 protein has a restricted mobility at 37 degrees C due to interaction with the erythrocyte cytoskeleton. 3. Oligosaccharide chains on the surface of human erythrocytes have been labelled with eosin-TSC. The motion of these chains has been investigated by combining transient dichroism studies in the microsecond time range with picosecond fluorescent depolarization measurements.
膜蛋白的旋转扩散可以通过检测闪光诱导的三重态探针或固有发色团的瞬态二色性来测量。以下应用说明了该方法。1. 已测量了掺入脂质小泡中的细菌视紫红质的各向异性衰减曲线。这些数据用于严格检验一个理论模型，该模型假设蛋白质仅围绕膜法线旋转。2. 研究了人红细胞膜中用曙红标记的带3蛋白的旋转扩散。这些测量说明了蛋白质旋转测量对于研究膜中蛋白质-蛋白质相互作用的价值。特别地，结果表明，由于与红细胞细胞骨架的相互作用，高达40%的带3蛋白在37摄氏度时具有受限的流动性。3. 人红细胞表面的寡糖链已用曙红-TSC标记。通过将微秒时间范围内的瞬态二色性研究与皮秒荧光去极化测量相结合，研究了这些链的运动。
