Laboratoire Léon Brillouin LLB, UMR12 CEA/CNRS, CEA Saclay, Gif-sur-Yvette, France.
Synchrotron SOLEIL, L'Orme des Merisiers, Saint Aubin BP48, Gif-sur-Yvette, France.
Methods Mol Biol. 2024;2843:73-94. doi: 10.1007/978-1-0716-4055-5_6.
Circular dichroism (CD) is a spectroscopic technique commonly used for the analysis of proteins. Particularly, it allows the determination of protein secondary structure content in various media, including the membrane environment. In this chapter, we present how CD applications can be used to analyze the interaction of proteins with bacterial outer membrane vesicles (OMVs). Most CD studies characterizing the structure of proteins inserted into membranes rely on artificial lipid bilayers, mimicking natural membranes. Nevertheless, these artificial models lack the important features of the true membrane, especially for the outer membrane of Gram-negative bacteria. These features include lipid diversity, glycosylation, and asymmetry. Here, we show how to analyze the interactions of proteins, either integral or peripheral, with OMVs in solution and with supported membranes of OMVs, using conventional CD and orientated circular dichroism (OCD). We explain how to decipher the spectroscopic signals to obtain information on the molecular structure of the protein upon its interaction with an OMV and through its potential insertion into an OMV membrane.
圆二色性（CD）是一种常用于分析蛋白质的光谱技术。特别是，它允许在各种介质中确定蛋白质二级结构含量，包括膜环境。在本章中，我们介绍了如何将 CD 应用于分析蛋白质与细菌外膜囊泡（OMV）的相互作用。大多数用于表征插入膜中的蛋白质结构的 CD 研究依赖于人工脂质双层，模拟天然膜。然而，这些人工模型缺乏真正膜的重要特征，特别是对于革兰氏阴性细菌的外膜。这些特征包括脂质多样性、糖基化和不对称性。在这里，我们展示了如何使用常规 CD 和定向圆二色性（OCD）分析蛋白质（无论是整合蛋白还是外周蛋白）与溶液中的 OMV 以及 OMV 支撑膜的相互作用。我们解释了如何解释光谱信号，以获取有关蛋白质与 OMV 相互作用时以及潜在插入 OMV 膜时其分子结构的信息。
