Bañuelos S, Muga A
Department of Biochemistry, University of the Basque Country, Bilbao, Spain.
J Biol Chem. 1995 Dec 15;270(50):29910-5. doi: 10.1074/jbc.270.50.29910.
The effect of membrane binding on the structure and stability of several conformers of alpha-lactalbumin was studied by infrared spectroscopy, circular dichroism, and fluorescence spectroscopy. In solution, under experimental conditions where all conformers interact with negatively charged membranes, they show significant conformational differences. However, binding to negatively charged membranes, which causes considerable changes in the structure of these conformers, leads to a remarkably similar protein conformation. The membrane-associated conformations are characterized by 1) a high helical content, greater than any of those found in solution, 2) a lack of stable tertiary structure, and 3) the disappearance of their thermotropic transition. These observations indicate that association with negatively charged membranes induces a conformational change within alpha-lactalbumin to a flexible, molten globule-like state.
通过红外光谱、圆二色光谱和荧光光谱研究了膜结合对α-乳白蛋白几种构象体结构和稳定性的影响。在溶液中，在所有构象体都与带负电荷的膜相互作用的实验条件下，它们表现出显著的构象差异。然而，与带负电荷的膜结合会导致这些构象体的结构发生相当大的变化，从而导致蛋白质构象非常相似。膜相关构象的特征为：1）高螺旋含量，高于溶液中发现的任何一种；2）缺乏稳定的三级结构；3）热致转变消失。这些观察结果表明，与带负电荷的膜结合会诱导α-乳白蛋白内的构象变化，使其转变为灵活的、类似熔球的状态。
