Hydrophobic effect in protein folding and other noncovalent processes involving proteins.
Hydrophobic effect in protein folding and other noncovalent processes involving proteins.
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DOI：
10.1073/pnas.86.21.8382
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发表时间：
1989-11
影响因子：
11.1
通讯作者：
Ruth S. Spolar;J. Ha;Record Mt
中科院分区：
文献类型：
--
作者：
Ruth S. Spolar;J. Ha;Record Mt
大的负标准热容量变化（Δ CP度远小于0）是从水中除去非极性表面的过程的标志，包括非极性溶质从水转移到非水相和蛋白质的折叠、聚集/缔合和配体结合反应[斯图尔特万特，J.M.（1977）Proc. Natl. Acad. Sci. USA 74，2236-2240]。最近，Baldwin [Baldwin，R. L.等人（1986）Proc. Acad. Sci. USA 83，8069-8072]提出蛋白质折叠的Δ CP程度可用于量化非极性表面的掩埋（疏水效应）对球状蛋白质稳定性的贡献。我们证明了三角洲CP度和水可及非极性表面积变化之间的相同相关性（Δ Anp）是从水到纯液相的非极性溶质的转移和小球状蛋白质的折叠获得的：Δ CP度/Δ Anp = -（0.28 +/- 0.05）（其中Δ Anp以A2表示，Δ CP度以cal.mol-1.K-1表示; 1 cal = 4.184 J）。这些相关性相同的事实证实了斯图尔特万特和Baldwin的提议，即疏水效应通常是δ CP度的主要贡献者，并提供了估算疏水驱动力贡献的直接方法（Δ Ghyd度）与非共价过程的标准自由能变化的关系，该非共价过程的特征在于在生理温度范围内具有大的负Δ CP度：Δ Ghyd度与（80 +/- 10）Δ CP度一致。
Large negative standard heat capacity changes (delta CP degree much less than 0) are the hallmark of processes that remove nonpolar surface from water, including the transfer of nonpolar solutes from water to a nonaqueous phase and the folding, aggregation/association, and ligand-binding reactions of proteins [Sturtevant, J. M. (1977) Proc. Natl. Acad. Sci. USA 74, 2236-2240]. More recently, Baldwin [Baldwin, R. L. (1986) Proc. Natl. Acad. Sci. USA 83, 8069-8072] proposed that the delta CP degree of protein folding could be used to quantify the contribution of the burial of nonpolar surface (the hydrophobic effect) to the stability of a globular protein. We demonstrate that identical correlations between the delta CP degree and the change in water-accessible nonpolar surface area (delta Anp) are obtained for both the transfer of nonpolar solutes from water to the pure liquid phase and the folding of small globular proteins: delta CP degree/delta Anp = -(0.28 +/- 0.05) (where delta Anp is expressed in A2 and delta CP degree is expressed in cal.mol-1.K-1; 1 cal = 4.184 J). The fact that these correlations are identical validates the proposals by both Sturtevant and Baldwin that the hydrophobic effect is in general the dominant contributor to delta CP degree and provides a straightforward means of estimating the contribution of the hydrophobic driving force (delta Ghyd degree) to the standard free energy change of a noncovalent process characterized by a large negative delta CP degree in the physiological temperature range: delta Ghyd degree congruent to (80 +/- 10)delta CP degree.