Copper鈥揚eptide Complex Structure and Reactivity When Found in Conserved His-Xaa-His Sequences
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- 作者：Ga Young Park ; Jung Yoon Lee ; Richard A. Himes ; Gnana S. Thomas ; Ninian J. Blackburn ; Kenneth D. Karlin
- 刊名：Journal of the American Chemical Society
- 出版年：2014
- 出版时间：September 10, 2014
- 年：2014
- 卷：136
- 期：36
- 页码：12532-12535
- 全文大小：303K
- ISSN：1520-5126
文摘
Oxygen-activating copper proteins may possess His-Xaa-His chelating sequences at their active sites and additionally exhibit imidiazole group 未N vs 蔚N tautomeric preferences. As shown here, such variations strongly affect copper ion鈥檚 coordination geometry, redox behavior, and oxidative reactivity. Copper(I) complexes bound to either 未-HGH or 蔚-HGH tripeptides were synthesized and characterized. Structural investigations using X-ray absorption spectroscopy, density functional theory calculations, and solution conductivity measurements reveal that 未-HGH forms the CuI dimer complex [{CuI(未-HGH)}2]2+ (1) while 蔚-HGH binds CuI to give the monomeric complex [CuI(蔚-HGH)]+ (2). Only 2 exhibits any reactivity, forming a strong CO adduct, [CuI(蔚-HGH)(CO)]+, with properties closely matching those of the copper monooxygenase PHM. Also, 2 is reactive toward O2 or H2O2, giving a new type of O2-adduct or CuII鈥揙OH complex, respectively.