The pressure-temperature phase diagram is important to our understanding of the physics of biomolecules. Compared to studies on temperature effects, studies of the pressure dependence of protein dynamic are rather limited. Molecular dynamics (MD) simulations with fine-tuned force fields (FFs) offer a powerful tool to explore the influence of thermodynamic conditions on proteins. Here we evaluate the transferability of the CHARMM36m (C36m) protein force field at varied pressures compared with NMR data using ubiquitin as a model protein. The pressure dependences of J couplings for hydrogen bonds and order parameters for internal motion are in good agreement with experiment. We demonstrate that the C36m FF combined with the Lennard-Jones particle-mesh Ewald (LJ-PME) method is suitable for simulations in a wide range of temperature and pressure. As the ubiquitin remains stable up to 2500 bar, we identify the mobility and stability of different hydrogen bonds in response to pressure. Based on those results, C36m is expected to be applied to more proteins in the future to further investigate protein dynamics under elevated pressures.

压力-温度相图对于我们理解生物分子的物理学很重要。与温度效应研究相比，蛋白质动力学的压力依赖性研究相当有限。具有微调力场 (FF) 的分子动力学 (MD) 模拟提供了一个强大的工具来探索热力学条件对蛋白质的影响。在这里，我们评估了 CHARMM36m (C36m) 蛋白质力场在不同压力下的可转移性，并与使用泛素作为模型蛋白质的 NMR 数据进行了比较。J的压力依赖性氢键的耦合和内部运动的有序参数与实验非常吻合。我们证明了 C36m FF 与 Lennard-Jones 粒子网格 Ewald (LJ-PME) 方法相结合适用于各种温度和压力下的模拟。由于泛素在高达 2500 巴的压力下仍保持稳定，我们确定了不同氢键响应压力的流动性和稳定性。基于这些结果，C36m 有望在未来应用于更多蛋白质，以进一步研究高压下的蛋白质动力学。