Structural Biophysics, X-ray and Neutron Science, Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark.
Methods Mol Biol. 2020;2141:569-584. doi: 10.1007/978-1-0716-0524-0_29.
Several intrinsically disordered proteins (IDPs) exhibit high affinity for lipid membranes. Among the different biophysical methods to probe protein-lipid interaction, neutron reflectometry (NR) can provide direct and structural detailed information on the location of the IDP with respect to the membrane. Supported lipid bilayers are commonly used as cell membrane models in such experiments. NR measurements can be collected on the supported lipid bilayer before and after the interaction with the IDP to characterize whether the protein molecules are mainly located on the membrane surface (interaction with the lipid headgroups), are penetrating into the hydrophobic region of the membrane (interaction with the lipid acyl chains), or are not interacting at all with the membrane. The lipid composition of the supported lipid bilayer can easily be tuned; hence the NR experiments can be designed to investigate selective IDP-lipid interactions.This chapter will describe the fundamental steps for performing an NR experiment and the subsequent data analysis aimed at characterizing IDP-lipid bilayer interactions. The specific case of an intrinsically disordered region (IDR) from the membrane protein Na/H exchanger isoform 1 (NHE1) will be used as an example, but the same protocol can be easily adapted to other IDPs.
几种无规卷曲蛋白质（IDP）对脂质膜表现出高亲和力。在探测蛋白质-脂质相互作用的不同生物物理方法中，中子反射率（NR）可以提供关于 IDP 相对于膜的位置的直接和结构详细信息。在这些实验中，通常使用支撑脂质双层作为细胞膜模型。NR 测量可以在与 IDP 相互作用之前和之后在支撑脂质双层上进行，以表征蛋白质分子主要位于膜表面（与脂质头部基团相互作用）、是否穿透膜的疏水区（与脂质酰基链相互作用），还是根本不与膜相互作用。支撑脂质双层的脂质组成可以轻松调整；因此，NR 实验可以设计为研究选择性 IDP-脂质相互作用。本章将描述执行 NR 实验的基本步骤和随后的数据分析，旨在表征 IDP-脂质双层相互作用。将以膜蛋白 Na/H 交换体同工型 1（NHE1）的无规卷曲区域（IDR）为例，但相同的方案可以轻松适用于其他 IDP。
