Niether Doreen, Sarter Mona, Koenig Bernd W, Fitter Jörg, Stadler Andreas M, Wiegand Simone
Institute of Biological Information Processing (IBI-4: Biomacromolecular Systems and Processes) & JARA-SOFT, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany.
I. Physikalisches Institut (IA) & JARA-SOFT, AG Biophysik, RWTH Aachen, Sommerfeldstrasse 14, 52074 Aachen, Germany.
Polymers (Basel). 2020 Feb 7;12(2):376. doi: 10.3390/polym12020376.
Thermophoretic behavior of a free protein changes upon ligand binding and gives access to information on the binding constants. The Soret effect has also been proven to be a promising tool to gain information on the hydration layer, as the temperature dependence of the thermodiffusion behavior is sensitive to solute-solvent interactions. In this work, we perform systematic thermophoretic measurements of the protein streptavidin (STV) and of the complex STV with biotin (B) using thermal diffusion forced Rayleigh scattering (TDFRS). Our experiments show that the temperature sensitivity of the Soret coefficient is reduced for the complex compared to the free protein. We discuss our data in comparison with recent quasi-elastic neutron scattering (QENS) measurements. As the QENS measurement has been performed in heavy water, we perform additional measurements in water/heavy water mixtures. Finally, we also elucidate the challenges arising from the quantiative thermophoretic study of complex multicomponent systems such as protein solutions.
游离蛋白质的热泳行为会因配体结合而发生变化，从而可获取有关结合常数的信息。索雷特效应也已被证明是获取有关水化层信息的一种很有前景的工具，因为热扩散行为的温度依赖性对溶质 - 溶剂相互作用很敏感。在这项工作中，我们使用热扩散强迫瑞利散射（TDFRS）对蛋白质抗生物素蛋白（STV）以及抗生物素蛋白与生物素（B）的复合物进行了系统的热泳测量。我们的实验表明，与游离蛋白质相比，复合物的索雷特系数的温度敏感性降低。我们将我们的数据与最近的准弹性中子散射（QENS）测量结果进行了比较讨论。由于QENS测量是在重水中进行的，我们在水/重水混合物中进行了额外的测量。最后，我们还阐明了对诸如蛋白质溶液等复杂多组分系统进行定量热泳研究时所面临的挑战。
