Amphipathic co-polymers such as styrene-maleic acid (SMA) have gained popularity over the last few years due to their ability and ease of use in solubilising and purifying membrane proteins in comparison to conventional methods of extraction such as detergents. SMA2000 is widely used for membrane protein studies and is considered as the optimal polymer for this technique. In this study a side-by-side comparison of SMA2000 with the polymer SZ30010 was carried out as both these polymers have similar styrene:maleic acid ratios and average molecular weights. Ability to solubilise, purify and stabilise membrane proteins was tested using three structurally different membrane proteins. Our results show that both polymers can be used to extract membrane proteins at a comparable efficiency to conventional detergent dodecylmaltoside (DDM). SZ30010 was found to give a similar protein yield and, SMALP disc size as SMA2000, and both polymers offered an increased purity and increased thermostability compared to DDM. Further investigation was conducted to investigate SMALP sensitivity to divalent cations. It was found that the sensitivity is polymer specific and not dependent on the protein encapsulated. Neither is it affected by the concentration of SMALPs. Larger divalent cations such as Co2+ and Zn2+ resulted in an increased sensitivity.

中文翻译：

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检查 SMALP 内膜蛋白的稳定性

与传统的提取方法（如去污剂）相比，两亲性共聚物（如苯乙烯-马来酸 (SMA)）在溶解和纯化膜蛋白方面的能力和易用性在过去几年中越来越受欢迎。SMA2000 广泛用于膜蛋白研究，被认为是该技术的最佳聚合物。在本研究中，我们对 SMA2000 与聚合物 SZ30010 进行了并排比较，因为这两种聚合物具有相似的苯乙烯:马来酸比率和平均分子量。使用三种结构不同的膜蛋白测试了溶解、纯化和稳定膜蛋白的能力。我们的结果表明，这两种聚合物都可用于提取膜蛋白，其效率与传统洗涤剂十二烷基麦芽糖苷 (DDM) 相当。发现 SZ30010 提供与 SMA2000 相似的蛋白质产量和 SMALP 圆盘尺寸，并且与 DDM 相比，两种聚合物都提供更高的纯度和更高的热稳定性。进行了进一步研究以研究 SMALP 对二价阳离子的敏感性。发现敏感性是聚合物特异性的并且不依赖于封装的蛋白质。它也不受 SMALP 浓度的影响。较大的二价阳离子如 Co2+ 和 Zn2+ 导致灵敏度增加。它也不受 SMALP 浓度的影响。较大的二价阳离子如 Co2+ 和 Zn2+ 导致灵敏度增加。它也不受 SMALP 浓度的影响。较大的二价阳离子如 Co2+ 和 Zn2+ 导致灵敏度增加。