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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Protein dynamics on different timescales
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Protein dynamics on different timescales

机译：不同时间尺度上的蛋白质动力学

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Structure and dynamics determine the function of proteins. This contribution discusses two aspects of protein dynamics, the structural fluctuation and the structural relaxation connected with conformational changes. Myoglobin and haemoglobin were investigated. To cover a wide time range different experimental techniques had to be used. Moreover, measurements in a large temperature regime were used to separate contributions from different modes of motions. Phonon assisted Mossbauer effect using synchrotron radiation allowed the study of the harmonic vibrations which have characteristic times of 1 fs to 0.6 ps. They are present in the whole temperature range from cryogenic to room temperature. With a combination of neutron structure analysis and incoherent neutron scattering it was possible to distinguish three types of hydrogen mean square displacements which are present only above a characteristic temperature T-c: These are the backbone-like (slower than about 100 ps), methyl-like (partly slower partly faster than about 100 ps) and lysine-like (faster than about 100 ps) displacements. The exceptional high energy resolution of Mossbauer absorption on Fe-57 allowed the measurement of quasi diffusive modes of molecular segments which have characteristic times slower than 1 ns and are present only above T-c. Conformational changes from the ligated to the unligated structure of myoglobin and haemoglobin were investigated by creating a metastable intermediate and observing the relaxation into the equilibrium conformation. A metastable state was obtained by X-ray irradiation. Structural relaxation was investigated as a function of time and temperature using the Mossbauer hyperfine interactions as indicator. Furthermore it was possible to measure intermediates created by photolysis of a ligand with temperature dependent X-ray structure analysis or time dependent X-ray structure analysis with the Lane technique. It was shown that the quasi diffusive structural fluctuations above T-c strongly facilitate structural relaxations. (c) 2006 Elsevier B.V. All rights reserved.
机译：结构和动力学决定蛋白质的功能。这项贡献讨论了蛋白质动力学的两个方面，即结构波动和与构象变化有关的结构松弛。研究了肌红蛋白和血红蛋白。为了涵盖很宽的时间范围，必须使用不同的实验技术。而且，在大温度范围内的测量被用来将来自不同运动模式的贡献分开。利用同步加速器辐射的声子辅助的Mossbauer效应可以研究特征时间为1 fs至0.6 ps的谐波振动。它们存在于从低温到室温的整个温度范围内。通过中子结构分析和非相干中子散射的组合，可以区分出仅在特征温度Tc以上才存在的三种氢均方位移：它们是类似骨架的（低于约100 ps），类似于甲基（部分较慢，部分较快于约100 ps）和类赖氨酸（比约100 ps快）位移。 Mossbauer在Fe-57上的吸收具有出色的高能量分辨率，因此可以测量特征时间低于1 ns且仅存在于T-c以上的分子链段的准扩散模式。通过创建亚稳态中间体并观察松弛到平衡构象，研究了肌红蛋白和血红蛋白从连接结构到未连接结构的构象变化。通过X射线照射获得亚稳态。使用Mossbauer超精细相互作用作为指标，研究结构弛豫随时间和温度的变化。此外，可以利用Lane技术通过温度依赖性X射线结构分析或时间依赖性X射线结构分析来测量由配体的光解产生的中间体。研究表明，T-c以上的准扩散结构性波动强烈促进了结构松弛。 （c）2006 Elsevier B.V.保留所有权利。

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