Department of Chemistry, University of Tennessee, Knoxville, USA.
Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, USA.
Angew Chem Int Ed Engl. 2023 Oct 23;62(43):e202306572. doi: 10.1002/anie.202306572. Epub 2023 Sep 19.
Styrene-maleic acid copolymers (SMAs), and related amphiphilic copolymers, are promising tools for isolating and studying integral membrane proteins in a native-like state. However, they do not exhibit this ability universally, as several reports have found that SMAs and related amphiphilic copolymers show little to no efficiency when extracting specific membrane proteins. Recently, it was discovered that esterified SMAs could enhance the selective extraction of trimeric Photosystem I from the thylakoid membranes of thermophilic cyanobacteria; however, these polymers are susceptible to saponification that can result from harsh preparation or storage conditions. To address this concern, we herein describe the development of α-olefin-maleic acid copolymers (αMAs) that can extract trimeric PSI from cyanobacterial membranes with the highest extraction efficiencies observed when using any amphiphilic copolymers, including diisobutylene-co-maleic acid (DIBMA) and functionalized SMA samples. Furthermore, we will show that αMAs facilitate the formation of photosystem I-containing nanodiscs that retain an annulus of native lipids and a native-like activity. We also highlight how αMAs provide an agile, tailorable synthetic platform that enables fine-tuning hydrophobicity, controllable molar mass, and consistent monomer incorporation while overcoming shortcomings of prior amphiphilic copolymers.
苯乙烯-马来酸共聚物（SMAs）和相关的两亲性共聚物是分离和研究天然状态下完整膜蛋白的有前途的工具。然而，它们并非普遍具有这种能力，因为有几项报告发现，SMAs 和相关的两亲性共聚物在提取特定膜蛋白时效率很低甚至没有。最近发现，酯化 SMA 可以增强从嗜热蓝藻的类囊体膜中提取三聚体 Photosystem I 的选择性；然而，这些聚合物容易受到皂化的影响，皂化可能是由于苛刻的制备或储存条件引起的。为了解决这个问题，我们在此描述了开发α-烯烃-马来酸共聚物（αMAs）的方法，该方法可以从蓝藻膜中提取三聚体 PSI，其提取效率高于使用任何两亲共聚物（包括二异丁烯-马来酸共聚物（DIBMA）和功能化 SMA 样品）时观察到的提取效率。此外，我们将展示αMAs 如何促进形成包含 PSI 的纳米盘，这些纳米盘保留了天然脂质的环和类似于天然的活性。我们还强调了αMAs 如何提供一个灵活的、可定制的合成平台，能够精细调整疏水性、可控的摩尔质量和一致的单体掺入，同时克服先前两亲共聚物的缺点。
