IBR (Instituto de Biología Molecular y Celular de Rosario), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK), Rosario, Argentina.
J Am Chem Soc. 2010 Aug 18;132(32):11191-6. doi: 10.1021/ja1037148.
Fet3p from Saccharomyces cerevisiae is a multicopper oxidase (MCO) which oxidizes Fe(2+) to Fe(3+). 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 Cu(2+) 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.
酿酒酵母的 Fet3p 是一种多铜氧化酶（MCO），能将 Fe(2+)氧化为 Fe(3+)。多年来，人们对该酶家族中不同铜中心的电子结构进行了广泛的研究和讨论，特别关注三核簇（TNC）中的交换耦合机制。我们利用 NMR 光谱技术，在完全金属化的氧化酶中定量了 3 型中心的交换耦合常数；该值在 Fet3p 中明显高于含有酪氨酸酶等分离型 3 型中心的蛋白质。我们还提供了证据表明 2 型和 3 型 Cu(2+)离子之间存在交换耦合，这支持了 TNC 与氧结合的晶体学证据。这项工作为将 NMR 应用于这些复杂体系奠定了基础。
