Department of Chemistry and Biomolecular Sciences, University of Ottawa, 10 Marie-Curie, Ottawa, ON Canada K1N 6N5.
Commun Biol. 2019 Nov 26;2:433. doi: 10.1038/s42003-019-0681-2. eCollection 2019.
Protein structures are dynamic, undergoing motions that can play a vital role in function. However, the link between primary sequence and conformational dynamics remains poorly understood. Here, we studied how conformational dynamics can arise in a globular protein by evaluating the impact of individual core-residue substitutions in DANCER-3, a streptococcal protein G domain β1 variant that we previously designed to undergo a specific mode of conformational exchange that has never been observed in the wild-type protein. Using a combination of solution NMR experiments and molecular dynamics simulations, we demonstrate that only two mutations are necessary to create this conformational exchange, and that these mutations work synergistically, with one destabilizing the native structure and the other allowing two new conformational states to be accessed on the energy landscape. Overall, our results show how dynamics can appear in a stable globular fold, a critical step in the molecular evolution of dynamics-linked functions.
蛋白质结构是动态的，会发生运动，这些运动在功能中起着至关重要的作用。然而，一级序列和构象动力学之间的联系仍然知之甚少。在这里，我们通过评估在 DANCER-3 中单个核心残基取代的影响来研究球状蛋白中构象动力学如何产生，DANCER-3 是一种链球菌蛋白 G 结构域 β1 变体，我们之前设计它以经历一种特定的构象交换模式，这种模式在野生型蛋白中从未观察到过。我们使用溶液 NMR 实验和分子动力学模拟的组合，证明仅需两个突变即可产生这种构象交换，并且这些突变具有协同作用，一个突变使天然结构不稳定，另一个突变使能量景观上能够进入两个新的构象状态。总的来说，我们的结果表明，在稳定的球状折叠中，动力学是如何出现的，这是与动力学相关功能的分子进化中的一个关键步骤。
