Dreydoppel Matthias, Achkinazi Mikhail, Krünholz Charlotte, Jordan Paula L, Weininger Ulrich
Institute of Physics, Biophysics, Martin-Luther-University Halle-Wittenberg, D-06120, Halle (Saale), Germany.
Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, D-79106, Freiburg, Germany.
Chembiochem. 2025 Jul 11;26(13):e202500183. doi: 10.1002/cbic.202500183. Epub 2025 Jun 4.
Aromatic ring flips are a hallmark of protein dynamics. They are mediated by either transient "breathing" motions in which the protein expands into the solvent or by transient internal rearrangement of void spaces. Therefore, they are excellent reporters of such transient protein fluctuations. To decipher the extent to which ring-flip dynamics are governed by the protein itself or by the aqueous solvent around it, the ring flip of the fully buried aromatic side chain of F52 in protein B1 domain of immunoglobulin G binding protein G(GB1) with experimentally feasible altered buffer conditions by nuclear magnetic resonance relaxation dispersion experiments is studied. Herein, it is found that ring-flip rate constants remain the same in all studied cases. Therefore, the ring-flip dynamic in the interior of GB1 is independent from the solvent and only depends on the protein itself. In addition, this study shows that ring flips are comparable within different buffer conditions.
芳香环翻转是蛋白质动力学的一个标志。它们由蛋白质向溶剂中扩展的瞬时“呼吸”运动或空隙空间的瞬时内部重排介导。因此，它们是此类蛋白质瞬时波动的优秀报告分子。为了解析环翻转动力学在多大程度上受蛋白质本身或其周围水性溶剂的控制，通过核磁共振弛豫分散实验，在实验可行的改变缓冲条件下，研究了免疫球蛋白G结合蛋白G（GB1）的B1结构域中完全埋藏的芳香族侧链F52的环翻转。在此发现，在所有研究的情况下，环翻转速率常数保持不变。因此，GB1内部的环翻转动力学与溶剂无关，仅取决于蛋白质本身。此外，这项研究表明，在不同缓冲条件下，环翻转是可比的。
