Direct measurement of barrier heights in protein folding
Direct measurement of barrier heights in protein folding
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DOI：
10.1021/ja055996y
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发表时间：
2005-12-28
影响因子：
15
通讯作者：
Muñoz, V
中科院分区：
文献类型：
--
作者：
Naganathan, AN;Sanchez-Ruiz, JM;Muñoz, V
蛋白质折叠反应研究的一个严重限制在于缺乏测量自由能垒绝对高度的实验方法。这是特别不幸的，因为如果折叠障碍很小，正如理论预测的那样，就有可能直接解决折叠机制。在这里，我们探讨了最近开发的一种从平衡差示扫描量热（DSC）实验中提取折叠屏障的方法的性能。为了测试该方法，我们将从可用 DSC 数据获得的 15 种蛋白质的热力学势垒高度与动力学实验中测量的折叠率进行了比较。这两个参数之间的相关性非常好（r2=0.9）并且具有与相同能量尺度一致的斜率。这些结果证实可以通过平衡 DSC 实验测量天然蛋白质的自由能垒。此外，测量的势垒高度通常很小（<8RT），对于快速折叠蛋白质来说是边缘的或不存在的。
A serious limitation in the study of protein folding reactions resides in the lack of experimental methods to measure the absolute height of the free energy barrier. This is particularly unfortunate given that if folding barriers are small, as theory predicts, it might be possible to resolve folding mechanisms directly. Here we explore the performance of a recently developed method to extract folding barriers from equilibrium differential scanning calorimetry (DSC) experiments. To test the method, we compare the thermodynamic barrier heights for 15 proteins obtained from available DSC data with the folding rates measured in kinetic experiments. The correlation between these two parameters is very good (r2= 0.9) and has a slope consistent with the same energy scale. These results confirm that it is possible to measure free energy barriers for natural proteins from equilibrium DSC experiments. Furthermore, the measured barrier heights are small (<8RT), in general, and marginal or nonexisting for fast-folding proteins.