Benga G, Strach S J
Biochim Biophys Acta. 1975 Jul 21;400(1):69-79. doi: 10.1016/0005-2795(75)90127-0.
The composite ESR spectra of nitroxide-maleimide spin-labelled albumin and mitochondrial membranes were investigated. It was found that the mobile spectrum (so called "weakly immobilized") is due to the probe free in solution; it could be removed by dialysis, by lowering the ratio of spin label to albumin or by using acid pH values. Similar degrees of mobility were noted with spectra of spin label in solutions with viscosities similar to that of albumin. The immobile spectrum (so called "strongly immobilized") is due to the binding of N-(1-oxyl-2,2,6,6-tetramethyl-4-piperidinyl)-maleimide to the proteins. Studies with modified albumins have shown that in this binding the free SH and amino groups are involved, but the three-dimensional structure offering conditions for hydrophobic binding is also required. The spectral parameters useful for evaluating conformational changes of proteins and an application to mitochondrial membranes are described.
对氮氧自由基 - 马来酰亚胺自旋标记白蛋白和线粒体膜的复合电子自旋共振（ESR）光谱进行了研究。发现移动光谱（所谓的“弱固定化”）是由于溶液中游离的探针所致；可通过透析、降低自旋标记与白蛋白的比例或使用酸性pH值将其去除。在粘度与白蛋白相似的溶液中，自旋标记的光谱也呈现出相似程度的移动性。固定光谱（所谓的“强固定化”）是由于N -（1 - 氧基 - 2,2,6,6 - 四甲基 - 4 - 哌啶基） - 马来酰亚胺与蛋白质结合所致。对修饰白蛋白的研究表明，这种结合涉及游离的巯基和氨基，但也需要提供疏水结合条件的三维结构。描述了可用于评估蛋白质构象变化的光谱参数及其在线粒体膜上的应用。
