Department of Biophysics and Physical Biochemistry, University of Regensburg, 93040 Regensburg, Federal Republic of Germany.
J Biomol NMR. 2010 Oct;48(2):71-83. doi: 10.1007/s10858-010-9438-4. Epub 2010 Aug 1.
Applying the chemical shift prediction programs SHIFTX and SHIFTS to a data base of protein structures with known chemical shifts we show that the averaged chemical shifts predicted from the structural ensembles explain better the experimental data than the lowest energy structures. This is in agreement with the fact that proteins in solution occur in multiple conformational states in fast exchange on the chemical shift time scale. However, in contrast to the real conditions in solution at ambient temperatures, the standard NMR structural calculation methods as well chemical shift prediction methods are optimized to predict the lowest energy ground state structure that is only weakly populated at physiological temperatures. An analysis of the data shows that a chemical shift prediction can be used as measure to define the minimum size of the structural bundle required for a faithful description of the structural ensemble.
运用化学位移预测程序 SHIFTX 和 SHIFTS 对已知化学位移的蛋白质结构数据库进行分析，我们发现，从结构集合中预测的平均化学位移比最低能量结构更好地解释了实验数据。这与这样一个事实是一致的，即在溶液中，蛋白质以快速交换的方式存在于多种构象状态，其交换速度快于化学位移时间尺度。然而，与溶液中在环境温度下的实际情况相反，标准的 NMR 结构计算方法以及化学位移预测方法都经过优化，以预测在生理温度下仅少量存在的最低能量基态结构。数据分析表明，化学位移预测可作为一种衡量标准，用于定义结构集合的结构束的最小尺寸，以准确描述结构集合。
