Derivation of Mean-Square Displacements for Protein Dynamics from Elastic Incoherent Neutron Scattering

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• 作者：Zheng Yi ; Yinglong Miao ; Jerome Baudry ; Nitin Jain ; Jeremy C. Smith
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：April 26, 2012
• 年：2012
• 卷：116
• 期：16
• 页码：5028-5036
• 全文大小：553K
• 年卷期：v.116,no.16(April 26, 2012)
• ISSN：1520-5207

文摘

The derivation of mean-square displacements from elastic incoherent neutron scattering (EINS) of proteins is examined, with the aid of experiments on camphor-bound cytochrome P450cam and complementary molecular dynamics simulations. It is shown that a q⁴ correction to the elastic incoherent structure factor (where q is the scattering vector) can be simply used to reliably estimate from the experiment both the average mean-square atomic displacement, 螖r² of the nonexchanged hydrogen atoms in the protein and its variance, 蟽². The molecular dynamics simulation results are in broad agreement with the experimentally derived 螖r² and 蟽² derived from EINS on instruments at two different energy resolutions, corresponding to dynamics on the 100 ps and 1 ns time scales. Significant dynamical heterogeneity is found to arise from methyl-group rotations. The easy-to-apply q⁴ correction extends the information extracted from elastic incoherent neutron scattering experiments and should be of wide applicability.