The rigidity and flexibility of a protein is reflected in its structural dynamics. Studies on protein dynamics often focus on flexibility and softness; this review focuses on protein structural rigidity. The extent of rigidity can be assessed experimentally with incoherent neutron scattering; a method that is complementary to molecular dynamics simulation. This experimental technique can provide information about protein dynamics in timescales of pico- to nanoseconds and at spatial scales of nanometers; these dynamics can help quantify the rigidity of a protein by indices such as force constant, Boson peak, dynamical transition, and dynamical heterogeneity. These indicators also reflect the rigidity of a protein's secondary and tertiary structures. In addition, the indices reveal how rigidity is influenced by different environmental parameters, such as hydration, temperature, pressure, and protein-protein interactions. Hydration affects both rigidity and softness more than other environmental factors. Interestingly, hydration affects harmonic and anharmonic motions in opposite ways. This difference is probably due to the protein's dynamic coupling with water molecules via hydrogen bonding.

中文翻译：

---

非相干中子散射揭示了蛋白质结构的刚性。

蛋白质的刚性和柔韧性反映在其结构动力学中。关于蛋白质动力学的研究通常集中在柔韧性和柔软性上。这篇综述着重于蛋白质的结构刚性。刚性程度可以通过非相干中子散射通过实验来评估。一种与分子动力学模拟互补的方法。这种实验技术可以提供有关皮秒至纳秒级和纳米级空间尺度上蛋白质动力学的信息。这些动力学可以通过诸如力常数，玻色子峰，动力学转变和动力学异质性等指标帮助量化蛋白质的刚性。这些指标还反映了蛋白质二级和三级结构的刚性。此外，这些指标还揭示了刚性如何受到不同环境参数的影响，例如水合作用，温度，压力和蛋白质间相互作用。与其他环境因素相比，水合作用对硬度和柔软度的影响更大。有趣的是，水合作用以相反的方式影响谐波和非谐运动。这种差异可能是由于蛋白质通过氢键与水分子的动态偶联。