Ervin J, Gruebele M
Departments of Chemistry, University of Illinois at Urbana-Champaign, IL 61801 USA.
J Biol Phys. 2002 Jun;28(2):115-28. doi: 10.1023/A:1019930203777.
A number of reaction coordinates have been proposed for reduced-dimensionalityrepresentations of a protein's folding free energy surface. We discuss in detail the entropic reaction coordinate Φ(T) = Δ S(†)ΔS, recently introduced to quantify the conservation of mutations and the location of the folding transition state based on experimental temperature-tuning data. Numerical simulations illustrate the advantages as well as the limitations of Φ(T). Φ(T) can be determined from experiment,computation, and analytical theory; Φ(T) can also be used to investigate structurally localized perturbations of the free energy surface. However, Φ(T) is only a relative reaction cordinate; furthermore, proteins undergo cold denaturation at sufficiently low temperatures, and care must be taken ininterpreting Φ(T) near the region where ∂ΔG/∂T = 0, particularly if the heat capacity change upon folding is small.
已经提出了许多反应坐标，用于蛋白质折叠自由能表面的降维表示。我们详细讨论了熵反应坐标Φ(T)=ΔS(†)ΔS，它最近被引入，用于根据实验温度调节数据来量化突变的保守性和折叠过渡态的位置。数值模拟说明了Φ(T)的优点和局限性。Φ(T)可以通过实验、计算和分析理论来确定；Φ(T)还可用于研究自由能表面的结构局部扰动。然而，Φ(T)只是一个相对反应坐标；此外，蛋白质在足够低的温度下会发生冷变性，在解释接近∂ΔG/∂T = 0的区域的Φ(T)时必须小心，特别是当折叠时的热容变化很小时。
