Hydration affects both harmonic and anharmonic nature of protein dynamics
Hydration affects both harmonic and anharmonic nature of protein dynamics
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DOI：
10.1529/biophysj.107.128546
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发表时间：
2008-09-15
影响因子：
3.4
通讯作者：
Kataoka, M.
中科院分区：
文献类型：
--
作者：
Nakagawa, H.;Joti, Y.;Kataoka, M.
为了了解水合作用对蛋白质动力学的影响，在不同水合水平的葡萄球菌核酸酶样品上进行了非弹性中子散射实验：脱水，部分水合和水合。在低温下，水合作用影响的集体运动的能量低于5 meV，而高能量的本地化运动是独立的水合作用。最显著的变化是玻色子峰值通过水合作用向更高能量移动，这表明能量景观上局部最小值处的谐波势硬化。240 K转变，观察到只有水合蛋白质。在300 K的显着的准弹性散射只观察到的水合样品，表明该过渡的起源是由水合水激活的运动。部分水合的样品的中子散射分布是非常相似的水合样品在100 K和200 K，而它是接近的脱水样品在300 K，表明部分水合是足以影响蛋白质动力学的谐波性质，并有一个阈值水合水平激活非谐运动。因此，水化水通过不同的方式控制谐波和非谐波蛋白质动力学。
To understand the effect of hydration on protein dynamics, inelastic neutron-scattering experiments were performed on staphylococcal nuclease samples at differing hydration levels: dehydrated, partially hydrated, and hydrated. At cryogenic temperatures, hydration affected the collective motions with energies lower than 5 meV, whereas the high-energy localized motions were independent of hydration. The prominent change was a shift of boson peak toward higher energy by hydration, suggesting a hardening of harmonic potential at local minima on the energy landscape. The 240 K transition was observed only for the hydrated protein. Significant quasielastic scattering at 300 K was observed only for the hydrated sample, indicating that the origin of the transition is the motion activated by hydration water. The neutron-scattering profile of the partially hydrated sample was quite similar to that of the hydrated sample at 100 K and 200 K, whereas it was close to the dehydrated sample at 300 K, indicating that partial hydration is sufficient to affect the harmonic nature of protein dynamics, and that there is a threshold hydration level to activate anharmonic motions. Thus, hydration water controls both harmonic and anharmonic protein dynamics by differing means.