Synthesis, Characterization and Applications of a Perdeuterated Amphipol
Synthesis, Characterization and Applications of a Perdeuterated Amphipol
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DOI：
10.1007/s00232-014-9656-x
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发表时间：
2014-10-01
影响因子：
2.4
通讯作者：
Popot, Jean-Luc
中科院分区：
文献类型：
--
作者：
Giusti, Fabrice;Rieger, Jutta;Popot, Jean-Luc
两极性聚合物是一种短的两亲性聚合物，可以替代膜蛋白（MPs）疏水表面的洗涤剂，使其在没有洗涤剂的情况下保持可溶性，同时保持稳定性。最广泛使用的双酚类化合物是A8-35，它由聚丙烯酸（PAA）主链接枝辛胺和异丙胺组成。在其众多应用中，A8-35已被证明对MPs的溶液态核磁共振研究特别有用，因为它可以消除来自表面活性剂质子的信号。本文对A8-35 （perDAPol）的合成及性能进行了研究。以氘化丙烯酸为原料，采用自由基聚合法制备了过氘化聚丙烯酸。随后用氘化胺接枝，得到perDAPol。氢化和perDAPol的数平均摩尔质量分别接近于4 kDa和5 kDa，通过四氢呋喃过甲基化后的尺寸排除色谱法从它们的PAA前体中推断出来。电喷雾电离-离子迁移率-质谱测定表明，两种apol的摩尔质量和分布非常相似。经中子散射，发现perDAPol的对比配点与120% D2O相似。在H-1-H-1核大修效应核磁共振谱中，它的贡献减少到与氢化A8-35相似的6%，适合在核磁共振谱中扩展应用。PerDAPol也可用于pol捕获MPs动力学的非弹性中子散射研究，以及小角度中子散射和分析性超离心。
Amphipols are short amphipathic polymers that can substitute for detergents at the hydrophobic surface of membrane proteins (MPs), keeping them soluble in the absence of detergents while stabilizing them. The most widely used amphipol, known as A8-35, is comprised of a polyacrylic acid (PAA) main chain grafted with octylamine and isopropylamine. Among its many applications, A8-35 has proven particularly useful for solution-state NMR studies of MPs, for which it can be desirable to eliminate signals originating from the protons of the surfactant. In the present work, we describe the synthesis and properties of perdeuterated A8-35 (perDAPol). Perdeuterated PAA was obtained by radical polymerization of deuterated acrylic acid. It was subsequently grafted with deuterated amines, yielding perDAPol. The number-average molar mass of hydrogenated and perDAPol, similar to 4 and similar to 5 kDa, respectively, was deduced from that of their PAA precursors, determined by size exclusion chromatography in tetrahydrofuran following permethylation. Electrospray ionization-ion mobility spectrometry-mass spectrometry measurements show the molar mass and distribution of the two APols to be very similar. Upon neutron scattering, the contrast match point of perDAPol is found to be similar to 120 % D2O. In H-1-H-1 nuclear overhauser effect NMR spectra, its contribution is reduced to similar to 6 % of that of hydrogenated A8-35, making it suitable for extended uses in NMR spectroscopy. PerDAPol ought to also be of use for inelastic neutron scattering studies of the dynamics of APol-trapped MPs, as well as small-angle neutron scattering and analytical ultracentrifugation.