从BSRF到HEPS

作为北京怀柔综合性国家科学中心的核心装置,高能同步辐射光源（High Energy Photon Source,简称HEPS）的建设如火如荼,基建工作已基本完成（建设实景照片如图1所示）,正处于设备安装阶段,将于2025年底顺利完成。届时世界领先水平的新一代同步辐射光源（参数见表1）^[1]将屹立在古老的长城脚下,为中国多学科领域研究能力的提升、产出世界一流的研究成果提供重要的研究支撑平台。     

X-ray absorption near-edge structure study on the configuration of Cu~(2+)/histidine complexes at different pH values

The local configurations around metal ions in metalloproteins are of great significance for understanding their biological functions. Cu~(2+)/histidine(His) is a typical complex existing in many metalloproteins and plays an important role in lots of physiological functions. The three-dimensional(3D) structural configurations of Cu~(2+)/His complexes at different p H values(2.5, 6.5, and 8.5) are quantitatively determined by x-ray absorption near-edge structure(XANES). Generally Cu~(2+)/His complex keeps an octahedral configuration consisting of oxygen atoms from water molecules and oxygen or nitrogen atoms from histidine molecules coordinated around Cu~(2+). It is proved in this work that the oxygen atoms from water molecules, when increasing the p H value from acid to basic value, are gradually substituted by the Ocarboxyl, Nam,and Nimfrom hisitidine molecules. Furthermore, the symmetries of Cu~(2+)/His complexes at pH 6.5 and pH 8.5 are found to be lower than at pH 2.5.