Reichenwallner Jörg, Hinderberger Dariush
Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany; Institute for Pharmacy and Biochemistry, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, D-55128 Mainz, Germany.
Biochim Biophys Acta. 2013 Dec;1830(12):5382-93. doi: 10.1016/j.bbagen.2013.04.031. Epub 2013 Apr 30.
Serum albumin is a major transport protein in mammals and is known to have at least seven binding sites for long-chain fatty acids (FAs).
We have devised a new electron paramagnetic resonance (EPR) spectroscopic approach to gain information on the functional structure of serum albumin in solution in a "coarse-grained" manner from the ligands' point of view. Our approach is based on using spin labeled (paramagnetic) stearic acids self-assembled with albumin and subsequent nanoscale distance measurements between the FAs using double electron-electron resonance spectroscopy (DEER). Simple continuous wave (CW) EPR spectroscopy, which allows for quantification of bound ligands, complements our studies.
Based on DEER nanoscale distance measurements, the functional solution structure of human serum albumin (HSA) has remarkably been found to have a much more symmetric distribution of entry points to the FA binding sites than expected from the crystal structure, indicating increased surface flexibility and plasticity for HSA in solution. In contrast, for bovine serum albumin (BSA), the entry point topology is in good agreement with that expected from the crystal structure of HSA. Changes in the solution structures between albumins can hence be revealed and extended to more albumins to detect functional differences at the nanoscale. Going beyond fundamental structural studies, our research platform is also excellently suited for general studies of protein-solvent interactions, temperature effects and ligand binding.
We discuss how our research platform helps illuminate protein dynamics and function and can be used to characterize albumin-based hybrid materials. This article is part of a Special Issue entitled Serum Albumin.
血清白蛋白是哺乳动物中的一种主要转运蛋白，已知其具有至少七个长链脂肪酸（FAs）结合位点。
我们设计了一种新的电子顺磁共振（EPR）光谱方法，以从配体的角度以“粗粒度”方式获取溶液中血清白蛋白功能结构的信息。我们的方法基于使用与白蛋白自组装的自旋标记（顺磁性）硬脂酸，并随后使用双电子-电子共振光谱（DEER）测量脂肪酸之间的纳米级距离。简单的连续波（CW）EPR光谱能够对结合的配体进行定量，对我们的研究起到了补充作用。
基于DEER纳米级距离测量，发现人血清白蛋白（HSA）的功能溶液结构中，脂肪酸结合位点的入口点分布比晶体结构预期的更加对称，这表明溶液中HSA的表面柔韧性和可塑性增加。相比之下，牛血清白蛋白（BSA）的入口点拓扑结构与HSA晶体结构预期的一致。因此，可以揭示白蛋白之间溶液结构的变化，并扩展到更多白蛋白以检测纳米级的功能差异。除了基础结构研究之外，我们的研究平台还非常适合蛋白质-溶剂相互作用、温度效应和配体结合的一般研究。
我们讨论了我们的研究平台如何有助于阐明蛋白质动力学和功能，以及如何用于表征基于白蛋白的杂化材料。本文是名为《血清白蛋白》的特刊的一部分。
