NMR Study of the Exchange Coupling in the Trinuclear Cluster of the Multicopper Oxidase Fet3p

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• 作者：Mara-Eugenia Zaballa ; Lynn Ziegler ; Daniel J. Kosman ; Alejandro J. Vila
• 刊名：Journal of the American Chemical Society
• 出版年：2010
• 出版时间：August 18, 2010
• 年：2010
• 卷：132
• 期：32
• 页码：11191-11196
• 全文大小：262K
• 年卷期：v.132,no.32(August 18, 2010)
• ISSN：1520-5126

文摘

Fet3p from Saccharomyces cerevisiae is a multicopper oxidase (MCO) which oxidizes Fe²⁺ to Fe³⁺. The electronic structure of the different copper centers in this family of enzymes has been extensively studied and discussed for years with a particular focus on the exchange coupling regime in the trinuclear cluster (TNC). Using NMR spectroscopy we have quantified the exchange coupling constant in the type 3 center in a fully metalated oxidase; this value in Fet3p is significantly higher than that reported for proteins containing isolated type 3 centers as tyrosinase. We also provide evidence of exchange coupling between the type 2 and the type 3 Cu²⁺ ions, which supports the crystallographic evidence of dioxygen binding to the TNC. This work provides the foundation for the application of NMR to these complex systems.