Protein Apparent Dielectric Constant and Its Temperature Dependence from Remote Chemical Shift Effects

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• 作者：Liaoyuan An ; Yefei Wang ; Ning Zhang ; Shihai Yan ; Ad Bax ; Lishan Yao
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：September 17, 2014
• 年：2014
• 卷：136
• 期：37
• 页码：12816-12819
• 全文大小：293K
• ISSN：1520-5126

文摘

A NMR protocol is introduced that permits accurate measurement of minute, remote chemical shift perturbations (CSPs), caused by a mutation-induced change in the electric field. Using protein GB3 as a model system, ¹H^N CSPs in K19A and K19E mutants can be fitted to small changes in the electric field at distal sites in the protein using the Buckingham equation, yielding an apparent dielectric constant 蔚_a of 8.6 卤 0.8 at 298 K. These CSPs, and their derived 蔚_a value, scale strongly with temperature. For example, CSPs at 313 K are about 鈭?0% smaller than those at 278 K, corresponding to an effective 蔚_a value of about 7.3 at 278 K and 10.5 at 313 K. Molecular dynamics simulations in explicit solvent indicate that solvent water makes a significant contribution to 蔚_a.