TEMPERATURE-DEPENDENCE OF THE HYDROPHOBIC INTERACTION IN PROTEIN FOLDING
TEMPERATURE-DEPENDENCE OF THE HYDROPHOBIC INTERACTION IN PROTEIN FOLDING
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DOI：
10.1073/pnas.83.21.8069
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发表时间：
1986-11-01
影响因子：
11.1
通讯作者：
BALDWIN, RL
中科院分区：
文献类型：
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作者：
BALDWIN, RL
准确的量热数据的热力学转移的六种液态烃到水已与溶解度数据相结合，以提供一个模型的温度依赖性的疏水相互作用蛋白质折叠。该模型适用于热容变化（Δ Cp）恒定的温度。传递熵（Δ S °）在温度（Ts）处的外推值达到零的情况惊人地相似（Ts = 112.8 °）。C .+-。2.2.degree. C）六种碳氢化合物。这一发现提供了对斯图尔特万特发现的经验关系的解释：比率Δ S °/Δ S在25 ° C下测量的Δ Cp。对于非极性物质从非水介质向水中的转移，C是常数。该比率的恒定性等同于Ts =常数。当应用于蛋白质折叠，烃模型给出的疏水相互作用的熵和焓变化展开的贡献估计，并通过差异，估计从其他来源的剩余贡献。在高温下展开时观察到的大焓变的主要部分来自疏水相互作用。疏水相互作用在22 ° C下从熵驱动改变。在113 ° C下被快速驱动。C.最后，碳氢化合物模型预测，展开时的比熵变与温度的关系曲线应在接近113 °处几乎相交。C，如Privalov所观察到的。
Accurate calorimetric data for the thermodynamics of transfer of six liquid hydrocarbons to water have been combined with solubility data to provide a model for the temperature dependence of the hydrophobic interaction in protein folding. The model applies at temperatures for which the change in heat capacity (.DELTA.Cp) is constant. The extrapolated value of the temperature (Ts) at which the entropy of transfer (.DELTA.S.degree.) reaches zero is strikingly similar (Ts = 112.8.degree. C .+-. 2.2.degree. C) for the six hydrocarbons. This finding provides an interpretation for the empirical relation discovered by Sturtevant: the ratio .DELTA.S.degree./.DELTA.Cp measured at 25.degree. C is constant for the transfer of nonpolar substances from nonaqueous media to water. Constancy of this ratio is equivalent to Ts = constant. When applied to protein folding, the hydrocarbon model gives estimates of the contributions of the hydrophobic interaction to the entropy and enthalpy changes on unfolding and, by difference, estimates of the residual contributions from other sources. The major share of the large enthalpy change observed on unfolding at high temperatures comes from the hydrophobic interaction. The hydrophobic interaction changes from being entropy-driven at 22.degree. C to being enthalpy-driven at 113.degree. C. Finally, the hydrocarbon model predicts that plots of the specific entropy change on unfolding versus temperature should nearly intersect close to 113.degree. C, as observed by Privalov.