Structure-based thermodynamic analysis of a coupled metal binding-protein folding reaction involving a zinc finger peptide
Structure-based thermodynamic analysis of a coupled metal binding-protein folding reaction involving a zinc finger peptide
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DOI：
10.1021/bi026621h
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发表时间：
2002-12-17
期刊：
影响因子：
2.9
通讯作者：
Berg, JM
中科院分区：
文献类型：
--
作者：
Blasie, CA;Berg, JM
用等温滴定量热法研究了典型的Cys（2）His（2）锌指肽CP-1与金属结合的热力学。在pH 7.0的胆碱缓冲液中，锌（II）与CP-1的结合显示Δ H度（obs）= -33.7 +/-0.8 kcal/mol的焓变。在金属结合过程中释放出一到两个质子。所用的胆碱缓冲液的质子化热相当大（~ 11.5千卡/摩尔），表明观察到的金属结合焓的一部分是由于缓冲液质子化。基于结构的热力学分析，包括从锌（II）的水释放的影响，似乎占与耦合金属结合蛋白质折叠过程serniquantitatively熵。反应的最强驱动力是与从锌（II）到半胱氨酸和组氨酸残基的四个键相关联的焓，与从锌（II）到水的键相比。钴（II）与CP-1的结合比锌（II）的结合少约7.6 kcal/mol的热动力。该值近似等于但略大于基于配体场稳定化能量考虑的预期值。
The thermodynamics of metal binding by the prototypical Cys(2)His(2) zinc finger peptide CP-1 has been examined through the use of isothermal titration calorimetry. In cholamine buffer at pH 7.0, the binding of zinc(II) to CP-1 shows an enthalpy change of DeltaHdegrees(obs) = -33.7 +/- 0.8 kcal/mol. Between one and two protons appear to be released accompanying the metal binding process. The heat of protonation of the cholamine buffer used is quite large (-11.5 kcal/mol), indicating that a portion of the observed metal binding enthalpy is due to buffer protonation. Structure-based thermodynamic analysis including the effect of water release from zinc(II) appears to account for the entropy associated with the coupled metal binding-protein folding process serniquantitatively. The strongest driving force for the reaction is the enthalpy associated with the four bonds from zinc(II) to cysteinate and histidine residues, compared with the bonds from zinc(II) to water. The binding of cobalt(II) to CP-1 is less enthalpically driven than the binding of zinc(II) by -7.6 kcal/mol. This value is approximately equal to, but slightly larger than, the expectation based on considerations of ligand field stabilization energy.