Engelke M, Behmann T, Ojeda F, Diehl H A
Department of Experimental Physics, FB1, University of Bremen, Germany.
Chem Phys Lipids. 1994 Jun 24;72(1):35-40. doi: 10.1016/0009-3084(94)90015-9.
Membrane fluidity measurements based on excimer formation of pyrene and pyrene derivatives as a measure of lateral diffusion yield a decreased fluidity in the presence of proteins [1-3]. It was the aim of our study to investigate whether the reduced excimer formation is due to a rigidifying effect of proteins on the whole membrane or if the fluorophore mobility is mainly hindered in the immediate protein environment. Resonance energy transfer in microsomal membranes between intrinsic tryptophan residues and pyrene were used to study the excimer formation rate in the vicinity of proteins. The excimer-to-monomer fluorescence ratio at excitation via resonance energy transfer is lower than that observed for the direct excitation. The results suggest that, because of a reduced fluidity in the neighbourhood of proteins, pyrene and pyrene fatty acids do not diffuse homogeneously in the membrane plane. A fluidity gradient exists from the membrane proteins to the bulk lipid.
基于芘及芘衍生物的准分子形成来测量膜流动性，以此作为横向扩散的一种度量方法，结果显示在有蛋白质存在的情况下膜流动性降低[1 - 3]。我们研究的目的是探究准分子形成减少是由于蛋白质对整个膜的刚性化作用，还是荧光团的流动性主要在蛋白质紧邻环境中受到阻碍。利用微粒体膜中内在色氨酸残基与芘之间的共振能量转移来研究蛋白质附近的准分子形成速率。通过共振能量转移激发时的准分子与单体荧光比率低于直接激发时观察到的比率。结果表明，由于蛋白质附近流动性降低，芘和芘脂肪酸在膜平面内扩散不均匀。从膜蛋白到主体脂质存在一个流动性梯度。
