Molecular Biophysics, Technische Universität Kaiserslautern, Erwin-Schrödinger-Strasse 13, 67663 Kaiserslautern, Germany.
Department of Neuroscience, University of Copenhagen, 2200 Copenhagen, Denmark.
Langmuir. 2023 Mar 14;39(10):3569-3579. doi: 10.1021/acs.langmuir.2c03019. Epub 2023 Feb 28.
Different amphiphilic co-polymers have been introduced to produce polymer-lipid particles with nanodisc structure composed of an inner lipid bilayer and polymer chains self-assembled as an outer belt. These particles can be used to stabilize membrane proteins in solution and enable their characterization by means of biophysical methods, including small-angle X-ray scattering (SAXS). Some of these co-polymers have also been used to directly extract membrane proteins together with their associated lipids from native membranes. Styrene/maleic acid and diisobutylene/maleic acid are among the most commonly used co-polymers for producing polymer-lipid particles, named SMALPs and DIBMALPs, respectively. Recently, a new co-polymer, named Glyco-DIBMA, was produced by partial amidation of DIBMA with the amino sugar -methyl-d-glucosamine. Polymer-lipid particles produced with Glyco-DIBMA, named Glyco-DIBMALPs, exhibit improved structural properties and stability compared to those of SMALPs and DIBMALPs while retaining the capability of directly extracting membrane proteins from native membranes. Here, we characterize the structure and lipid composition of Glyco-DIBMALPs produced with either 1-palmitoyl-2-oleoyl--glycero-3-phosphocholine (POPC) or 1,2-dimyristoyl--glycero-3-phosphocholine (DMPC). Glyco-DIBMALPs were also prepared with mixtures of either POPC or DMPC and cholesterol at different mole fractions. We estimated the lipid content in the Glyco-DIBMALPs and determined the particle structure and morphology by SAXS. We show that the Glyco-DIBMALPs are nanodisc-like particles whose size and shape depend on the polymer/lipid ratio. This is relevant for designing nanodisc particles with a tunable diameter according to the size of the membrane protein to be incorporated. We also report that the addition of >20 mol % cholesterol strongly perturbed the formation of Glyco-DIBMALPs. Altogether, we describe a detailed characterization of the Glyco-DIBMALPs, which provides relevant inputs for future application of these particles in the biophysical investigation of membrane proteins.
不同的两亲共聚物已被引入，以产生具有纳米盘结构的聚合物-脂质颗粒，该结构由内部脂质双层和聚合物链自组装而成的外部带组成。这些颗粒可用于稳定溶液中的膜蛋白，并通过生物物理方法（包括小角 X 射线散射（SAXS））对其进行表征。其中一些共聚物还被用于直接从天然膜中提取膜蛋白及其相关脂质。苯乙烯/马来酸和二异丁烯/马来酸是最常用于生产聚合物-脂质颗粒的共聚物，分别命名为 SMALPs 和 DIBMALPs。最近，一种新的共聚物，命名为 Glyco-DIBMA，通过 DIBMA 与氨基糖 -甲基-d-葡萄糖胺的部分酰胺化反应而产生。用 Glyco-DIBMA 制备的聚合物-脂质颗粒，命名为 Glyco-DIBMALPs，与 SMALPs 和 DIBMALPs 相比，具有改善的结构特性和稳定性，同时保持直接从天然膜中提取膜蛋白的能力。在这里，我们对用 1-棕榈酰基-2-油酰基--甘油-3-磷酸胆碱（POPC）或 1,2-二肉豆蔻酰基--甘油-3-磷酸胆碱（DMPC）制备的 Glyco-DIBMALPs 的结构和脂质组成进行了表征。还制备了 Glyco-DIBMALPs 与 POPC 或 DMPC 与胆固醇的混合物，摩尔分数不同。我们估计了 Glyco-DIBMALPs 中的脂质含量，并通过 SAXS 确定了颗粒的结构和形态。我们表明，Glyco-DIBMALPs 是纳米盘样颗粒，其大小和形状取决于聚合物/脂质的比例。这对于根据要掺入的膜蛋白的大小设计具有可调直径的纳米盘颗粒是相关的。我们还报告说，胆固醇的添加量超过 20mol％会强烈干扰 Glyco-DIBMALPs 的形成。总之，我们描述了 Glyco-DIBMALPs 的详细特征，这为这些颗粒在膜蛋白的生物物理研究中的未来应用提供了相关的输入。
