Physical origin of anharmonic dynamics in proteins: new insights from resolution-dependent neutron scattering on homomeric polypeptides.
Physical origin of anharmonic dynamics in proteins: new insights from resolution-dependent neutron scattering on homomeric polypeptides.
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蛋白质非谐动力学的物理起源：来自同聚多肽上分辨率依赖性中子散射的新见解。
DOI：
10.1103/physrevlett.109.128102
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发表时间：
2012
影响因子：
8.6
通讯作者：
A. Cupane
中科院分区：
文献类型：
--
作者：
G. Schirò;F. Natali;A. Cupane
中子散射揭示了多肽链中复杂的动力学，其中有两个主要的不和谐性起始点，其物理起源和生物学作用仍然存在争议。在这项研究中，通过使用不同能量分辨率的弹性中子散射研究了策略性选择的同聚多肽的动力学，并与真实蛋白质的动力学进行了比较。我们的数据强调了非谐转变温度和波动幅度对能量分辨率的依赖性，我们用蛋白质水合水能量景观的两点模型定量地解释了这一点。实验数据强烈表明，蛋白质动态转变不仅仅是分辨率效应，而是由真实的物理效应引起的。蛋白质动态转变获得的激活势垒和自由能值使我们能够与超冷承压水的两井相互作用势联系起来，以解释低密度→高密度液-液转变。
Neutron scattering reveals a complex dynamics in polypeptide chains, with two main onsets of anharmonicity whose physical origin and biological role are still debated. In this study the dynamics of strategically selected homomeric polypeptides is investigated with elastic neutron scattering using different energy resolutions and compared with that of a real protein. Our data spotlight the dependence of anharmonic transition temperatures and fluctuation amplitudes on energy resolution, which we quantitatively explain in terms of a two-site model for the protein-hydration water energy landscape. Experimental data strongly suggest that the protein dynamical transition is not a mere resolution effect but is due to a real physical effect. Activation barriers and free energy values obtained for the protein dynamical transition allow us to make a connection with the two-well interaction potential of supercooled-confined water proposed to explain a low-density→high-density liquid-liquid transition.