Picosecond to nanosecond dynamics provide a source of conformational entropy for protein folding.
Picosecond to nanosecond dynamics provide a source of conformational entropy for protein folding.
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皮秒到纳秒动力学为蛋白质折叠提供了构象熵的来源。
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
T. Seydel
中科院分区：
文献类型：
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作者：
A. Stadler;F. Demmel;J. Ollivier;T. Seydel
在稳定的平衡条件下，肌红蛋白可以被困在完全折叠的结构、部分折叠的熔融球体和未展开的状态中。本文报道了载脂蛋白和全肌红蛋白在溶液中不同折叠构象状态的构象动力学实验研究。利用中子飞行时间和中子后向散射光谱在皮秒和纳秒时间尺度上探测了蛋白质的整体扩散和分子内部运动。发现蛋白质的整体扩散依赖于蛋白质的α-螺旋含量，这表明大分子上的电荷增加了蛋白质的短期扩散。在纳秒时间尺度上，由于蛋白质纠缠和与邻近大分子的相互作用，可以看到熔融小球的凝胶状相，这是由于全局扩散系数的降低。对所研究的结构状态确定了内部蛋白质动力学的扩散系数、停留时间和松弛时间以及局部内部运动的均方根位移。从测量的均方根位移中提取蛋白质的未折叠和部分折叠或完全折叠构象之间的构象熵ΔSconf的差异。利用文献中的热力学参数和实验确定的ΔSconf值，我们可以确定不同折叠态的水化壳ΔShydr的熵贡献。我们的结果指出蛋白质的构象熵和水合壳对肌红蛋白的稳定性和折叠的相关性。
Myoglobin can be trapped in fully folded structures, partially folded molten globules, and unfolded states under stable equilibrium conditions. Here, we report an experimental study on the conformational dynamics of different folded conformational states of apo- and holomyoglobin in solution. Global protein diffusion and internal molecular motions were probed by neutron time-of-flight and neutron backscattering spectroscopy on the picosecond and nanosecond time scales. Global protein diffusion was found to depend on the α-helical content of the protein suggesting that charges on the macromolecule increase the short-time diffusion of protein. With regard to the molten globules, a gel-like phase due to protein entanglement and interactions with neighbouring macromolecules was visible due to a reduction of the global diffusion coefficients on the nanosecond time scale. Diffusion coefficients, residence and relaxation times of internal protein dynamics and root mean square displacements of localised internal motions were determined for the investigated structural states. The difference in conformational entropy ΔSconf of the protein between the unfolded and the partially or fully folded conformations was extracted from the measured root mean square displacements. Using thermodynamic parameters from the literature and the experimentally determined ΔSconf values we could identify the entropic contribution of the hydration shell ΔShydr of the different folded states. Our results point out the relevance of conformational entropy of the protein and the hydration shell for stability and folding of myoglobin.
影响因子：
3.3
作者：
Grimaldo, Marco;Roosen-Runge, Felix;Seydel, Tilo
通讯作者：
Seydel, Tilo
影响因子：
5.6
作者：
Eliezer, D;Wright, PE
通讯作者：
Wright, PE
影响因子：
56.9
作者：
HUGHSON, FM;WRIGHT, PE;BALDWIN, RL
通讯作者：
BALDWIN, RL