Multi‐copper oxidases (MCOs) are enzymes of significant interest in biotechnology due to their efficient catalysis of oxygen reduction to water, making them valuable in sustainable energy production and bio‐electrochemical applications. This study employs time‐dependent density functional theory (TDDFT) to investigate the electronic structure and spectroscopic properties of the Type 1 (T1) copper site in Azurin, which serves as a model for similar sites in MCOs. Four model complexes of varying complexity were derived from the T1 site, including 3 three‐coordinate models and 1 four‐coordinate model with axial methionine ligation, to explore the impact of molecular branches and axial coordination. Calculations using ωB97X‐D3 functional, def2‐TZVP basis set, and conductor‐like polarizable continuum model (CPCM) solvation model reproduced key experimental spectral features, with increased model complexity improving agreement, particularly for the ~400 cm−1 band splitting in resonance Raman spectra. This work enhances our understanding of T1 copper sites' electronic properties and spectra, bridging the gap between simplified models and complex proteins. The findings contribute to the interpretation of spectroscopic data in blue copper proteins and may inform future studies on similar biological systems.

中文翻译：

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配体复杂性对 1 型铜位点光谱特性的影响：一项理论研究


多氧化铜酶 （MCO） 是生物技术中具有重要意义的酶，因为它们可以有效地催化氧还原为水，使其在可持续能源生产和生物电化学应用中具有重要价值。本研究采用时间依赖性密度泛函理论 （TDDFT） 来研究 Azurin 中 1 型 （T1） 铜位点的电子结构和光谱特性，该位点可作为 MCO 中类似位点的模型。从 T1 位点衍生出 4 个复杂程度不同的模型复合物，包括 3 个三坐标模型和 1 个轴向蛋氨酸连接的四坐标模型，以探讨分子分支和轴向配位的影响。使用 ωB97X-D3 泛函、def2-TZVP 基集和导体状极化连续谱模型 （CPCM） 溶剂化模型的计算再现了关键的实验光谱特征，模型复杂性的增加提高了一致性，特别是对于共振拉曼光谱中的 ~400 cm-1 带分裂。这项工作增强了我们对 T1 铜位点的电子性质和光谱的理解，弥合了简化模型和复杂蛋白质之间的差距。这些发现有助于解释蓝铜蛋白中的光谱数据，并可能为未来对类似生物系统的研究提供信息。