Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble, France.
Phys Chem Chem Phys. 2020 Sep 7;22(33):18507-18517. doi: 10.1039/d0cp01857k. Epub 2020 Aug 11.
Protein denaturation in concentrated solutions consists of the unfolding of the native protein structure, and subsequent cross-linking into clusters or gel networks. While the kinetic evolution of structure has been studied for some cases, the underlying microscopic dynamics of proteins has so far been neglected. However, protein dynamics is essential to understand the specific nature of assembly processes, such as diffusion-limited growth, or vitrification of dense liquids. Here, we present a study on thermal denaturation of concentrated solutions of bovine serum albumin (BSA) in DO with and without NaCl. Using small-angle scattering, we provide information on structure before, during and after denaturation. Using quasi-elastic neutron scattering, we monitor in real-time the microscopic dynamics and dynamical confinement throughout the entire denaturation process covering protein unfolding and cross-linking. After denaturation, the protein dynamics is slowed down in salty solutions compared to those in pure water, while the stability and dynamics of the native solution appears unaffected by salt. The approach presented here opens opportunities to link microscopic dynamics to emerging structural properties, with implications for assembly processes in soft and biological matter.
在高浓度溶液中，蛋白质变性包括天然蛋白质结构的展开，以及随后的交联成簇或凝胶网络。虽然已经研究了某些情况下结构的动力学演化，但迄今为止一直忽略了蛋白质的微观动力学。然而，蛋白质动力学对于理解组装过程的特定性质至关重要，例如扩散限制生长或密集液体的玻璃化。在这里，我们研究了牛血清白蛋白（BSA）在 DO 中的浓缩溶液在有和没有 NaCl 的情况下的热变性。使用小角散射，我们在变性前后提供了结构信息。使用准弹性中子散射，我们实时监测整个变性过程中蛋白质展开和交联过程中的微观动力学和动力学限制。变性后，与在纯水中相比，盐溶液中的蛋白质动力学减慢，而盐对天然溶液的稳定性和动力学似乎没有影响。这里提出的方法为将微观动力学与新兴结构特性联系起来提供了机会，这对软物质和生物物质中的组装过程具有重要意义。
