Anandan Anandhi, Vrielink Alice
School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia.
Adv Exp Med Biol. 2016;922:13-28. doi: 10.1007/978-3-319-35072-1_2.
Detergents play a significant role in structural and functional characterisation of integral membrane proteins (IMPs). IMPs reside in the biological membranes and exhibit a great variation in their structural and physical properties. For in vitro biophysical studies, structural and functional analyses, IMPs need to be extracted from the membrane lipid bilayer environment in which they are found and purified to homogeneity while maintaining a folded and functionally active state. Detergents are capable of successfully solubilising and extracting the IMPs from the membrane bilayers. A number of detergents with varying structure and physicochemical properties are commercially available and can be applied for this purpose. Nevertheless, it is important to choose a detergent that is not only able to extract the membrane protein but also provide an optimal environment while retaining the correct structural and physical properties of the protein molecule. Choosing the best detergent for this task can be made possible by understanding the physical and chemical properties of the different detergents and their interaction with the IMPs. In addition, understanding the mechanism of membrane solubilisation and protein extraction along with crystallisation requirements, if crystallographic studies are going to be undertaken, can help in choosing the best detergent for the purpose. This chapter aims to present the fundamental properties of detergents and highlight information relevant to IMP crystallisation. The first section of the chapter reviews the physicochemical properties of detergents and parameters essential for predicting their behaviour in solution. The second section covers the interaction of detergents with the biologic membranes and proteins followed by their role in membrane protein crystallisation. The last section will briefly cover the types of detergent and their properties focusing on custom designed detergents for membrane protein studies.
去污剂在整合膜蛋白（IMPs）的结构和功能表征中起着重要作用。整合膜蛋白存在于生物膜中，其结构和物理性质差异很大。对于体外生物物理研究、结构和功能分析，需要从发现整合膜蛋白的膜脂双层环境中提取它们，并纯化至均质状态，同时保持折叠和功能活性状态。去污剂能够成功地将整合膜蛋白从膜双层中溶解和提取出来。许多具有不同结构和物理化学性质的去污剂在市场上有售，可用于此目的。然而，重要的是选择一种不仅能够提取膜蛋白，而且能在保留蛋白质分子正确结构和物理性质的同时提供最佳环境的去污剂。通过了解不同去污剂的物理和化学性质及其与整合膜蛋白的相互作用，可以为这项任务选择最佳去污剂。此外，如果要进行晶体学研究，了解膜溶解和蛋白质提取的机制以及结晶要求，有助于为此目的选择最佳去污剂。本章旨在介绍去污剂的基本性质，并突出与整合膜蛋白结晶相关的信息。本章的第一部分回顾了去污剂的物理化学性质以及预测其在溶液中行为所需的参数。第二部分涵盖了去污剂与生物膜和蛋白质的相互作用，以及它们在膜蛋白结晶中的作用。最后一部分将简要介绍去污剂的类型及其性质，重点是为膜蛋白研究定制设计的去污剂。
