PROTEINS AT LIQUID INTERFACES : ROLE OF THE MOLTEN GLOBULE STATE
PROTEINS AT LIQUID INTERFACES : ROLE OF THE MOLTEN GLOBULE STATE
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DOI：
10.1016/0927-7765(93)01116-9
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发表时间：
1994-09
期刊：
影响因子：
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通讯作者：
E. Dickinson;Y. Matsumura
中科院分区：
文献类型：
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作者：
E. Dickinson;Y. Matsumura
综述了近年来对蛋白质在液体界面上的结构和动力学的研究进展，特别是对蛋白质稳定乳状液中油水界面上的吸附层的研究。我们讨论的重要性，分子的灵活性，在确定吸附层的性质和易于交换的蛋白质分子之间的混合系统的散装和表面。虽然几乎无规共聚物的统计模型可用于描述无序蛋白质如β-酪蛋白的吸附，但这种表示对于吸附的球状蛋白质是不现实的，球状蛋白质通常是具有位于天然状态和完全未折叠形式之间某处的结构的紧凑的可变形大分子颗粒。有人提出，这种状态的吸附球状蛋白质在液体界面接近什么是现在所谓的“熔融球”的状态。这是球状蛋白质的部分变性状态，其保留了天然蛋白质的有序二级结构而不是三级结构。我们描述了产生熔融球态的各种方法，并详细回顾了α-乳白蛋白熔融球态的实验证据。最后讨论了α-乳白蛋白的表面活性以及在酸性pH和乙二胺四乙酸存在下α-乳白蛋白和β-乳球蛋白在乳状液中的竞争吸附。这一讨论显示了熔融球态的概念如何为蛋白质结构与液体界面吸附层性质之间的关系提供了新的见解。
Recent advances in understanding the structure and dynamics of proteins at liquid interfaces are reviewed with particular reference to adsorbed layers at the oil—water interface in protein-stabilized emulsions. We discuss the importance of molecular flexibility in determining the properties of adsorbed layers and the ease of exchange of protein molecules between bulk and surface in mixed systems. While a statistical model of a nearly random copolymer can be used to describe the adsorption of a disordered protein such as β-casein, such a representation is unrealistic for an adsorbed globular protein, which is typically a compact deformable macromolecular particle having a structure lying somewhere between the native state and the completely unfolded form. It is proposed that such a state of an adsorbed globular protein at a liquid interface is close to what is now called the “molten globule” state. This is the partially denatured state of a globular protein which retains the ordered secondary structure but not the tertiary structure of the native protein. We describe the various ways of producing the molten globule state, and we review the experimental evidence for the molten globule state of α-lactalbumin in some detail. In the final part of the paper, we discuss some new results on the surface activity of α-lactalbumin and the competitive adsorption of α-lactalbumin and β-lactoglobulin in emulsions at acidic pH or in the presence of ethylenediaminetetraacetic acid. This discussion shows how the concept of the molten globule state provides new insight into the relationship between protein structure and the properties of adsorbed layers at liquid interfaces.