Thermodynamics of Metal Ion Binding. 1. Metal Ion Binding by Wild-Type Carbonic Anhydrase
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- 作者：Charles A. DiTusa ; Trine Christensen ; Keith A. McCall ; Carol A. Fierke ; and Eric J. Toone
- 刊名：Biochemistry
- 出版年：2001
- 出版时间：May 8, 2001
- 年：2001
- 卷：40
- 期：18
- 页码：5338 - 5344
- 全文大小：121K
- 年卷期：v.40,no.18(May 8, 2001)
- ISSN：1520-4995
文摘
Understanding the energetic consequences of molecular structure in aqueous solution is aprerequisite to the rational design of synthetic motifs with predictable properties. Such properties includeligand binding and the collapse of polymer chains into discrete three-dimensional structures. Despiteadvances in macromolecular structure determination, correlations of structure with high-resolutionthermodynamic data remain limited. Here we compare thermodynamic parameters for the binding of Zn(II),Cu(II), and Co(II) to human carbonic anhydrase II. These calorimetrically determined values are interpretedin terms of high-resolution X-ray crystallographic data. While both zinc and cobalt are bound with a 1:1stoichiometry, CAII binds two copper ions. Considering only the high-affinity site, there is a diminutionin the enthalpy of binding through the series Co(II) 
Zn(II) Cu(II) that mirrors the enthalpy of hydration;this observation reinforces the notion that the thermodynamics of solute association with water is at leastas important as the thermodynamics of solute-solute interaction and that these effects must be consideredwhen interpreting association in aqueous solution. Additionally, 
Cp data suggest that zinc binding toCAII proceeds with a greater contribution from desolvation than does binding of either copper or cobalt,suggesting Nature optimizes binding by optimizing desolvation.
Zn(II) Cu(II) that mirrors the enthalpy of hydration;this observation reinforces the notion that the thermodynamics of solute association with water is at leastas important as the thermodynamics of solute-solute interaction and that these effects must be consideredwhen interpreting association in aqueous solution. Additionally, Cp data suggest that zinc binding toCAII proceeds with a greater contribution from desolvation than does binding of either copper or cobalt,suggesting Nature optimizes binding by optimizing desolvation.