X-ray absorption near edge structure (XANES) spectra of blue copper proteins, amicyanin and azurin, in the solution state were measured in the copper L₃-edge energy region. The absorption peak energies were quite similar for both proteins, while the main edge region for azurin was broader than that for amicyanin, owing to more pronounced shoulder spectral features in the former. Ab initio calculations at the whole protein level qualitatively reproduced the experimental spectra well. The relative X-ray absorption intensities suggest that the degree of covalency of the copper–ligand bond at the active site was weaker for amicyanin than that for azurin.

中文翻译：

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溶液态下 amicyanin 和 azurin 的蓝铜中心的电子结构


在铜 L₃ 边缘能量区测量了蓝铜蛋白、酰胺花青素和天青素在溶液状态下的 X 射线吸收近边缘结构 （XANES） 光谱。两种蛋白质的吸收峰能量非常相似，而 azurin 的主要边缘区域比 amicyanin 更宽，因为前者具有更明显的肩光谱特征。全蛋白水平的 Ab 头计算定性地再现了实验光谱。相对 X 射线吸收强度表明，酰胺青素在活性位点的铜-配体键的共价程度比 Azurin 弱。