Model-Free Approach beyond the Borders of Its Applicability

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• 作者：Korzhnev ; Dmitry M. ; Orekhov ; Vladislav Yu. ; Arseniev ; Alexander S.
• 刊名：Journal of Magnetic Resonance
• 出版年：1997
• 出版时间：August, 1997
• 年：1997
• 卷：127
• 期：2
• 页码：184-191
• 全文大小：177 K

文摘

Model calculations presented in this article show that commonly used methodology of¹⁵N relaxation data analysis completely fails in detecting nanosecond time scale motions if the major part of the molecule is involved in these motions. New criteria are introduced for the detection of such cases, based on the dependence of the apparent overall correlation time, derived from theT₁/T₂ratio, on the spectrometer frequency. Correctly estimating the overall rotation correlation time τ_Rwas shown to play the key role in model-free data analysis. It is found, however, that in cases of slow internal motions with characteristic times of more than 3–4 ns, the effective τ_Rprovided by theT₁/T₂ratio for individual amide nitrogens can be used for the characterization of the fast picosecond internal dynamics.