氧合血红素中Fe-O_(2)键的本质与探索  

The nature of Fe-O_(2) bond of oxyheme complexes

作　　者：李剑峰 Jianfeng Li(College of Materials Science and Opto-Electronic Technology,University of Chinese Academy of Sciences,Beijing 101408,China)

机构地区：[1]中国科学院大学材料科学与光电技术学院,北京101408

出　　处：《中国科学：化学》2022年第8期1253-1258,共6页SCIENTIA SINICA Chimica

基　　金：中国科学院先导专项(编号:XDB28000000);国家自然科学基金(编号:21771176,21977093)资助项目。

摘　　要：O_(2)是生命中最重要的双原子分子之一,但是氧合血红素中Fe-O_(2)键的本质问题却一直没有彻底解决,延续至今.争论主要存在于Fe-O_(2)键的电子结构、穆斯堡尔谱性质等方面.Fe-O_(2)键本身的复杂性,使得难以依靠单一模型解决所有问题.本文认为依靠不同模型,突出重点,获得多层次、多角度的分子结构信息,再深入到产物电子结构,是更切实际的研究思路.因此,依据蛋白环境,提出氢键与共价键连接轴向配体两个模型策略.这两种策略可望抑制无序,排除干扰,提供新的Fe-O_(2)键空间形态,从而获得新的电子结构信息.两类模型在合成化学中已有所体现,但是尚无氧合反应产物得到分离,因此是可行而紧迫的研究课题.基于已有的研究积累,本文同时强调多温度单晶表征,以观察随温度改变而发生的氧分子动态行为.相关研究工作可以深入到Fe-O_(2)键问题新的研究层面,收获新的科学数据,丰富生物无机理论,对基于血红素模型的仿生材料的研究也具有指导意义.Dioxygen(O_(2))is one of the most important diatomic molecules in the nature and life.In spite of a long history of study on the interactions of dioxygen with the oxygen-carrying and-storing heme complexes,there are a number of scientific debates concerning the geometric,electronic,and biophysical properties.These issues include the geometry of the bound dioxygen,the perplexing nature of the(diamagnetic)electronic structure,the dynamics of the Fe-O_(2) group in the heme environment,the relative orientation of the bound dioxygen with respect to the plane of the transhistidine,and the unusual and intriguing features of Mossbauer properties.Herein,we propose two strategies on the design and synthesis of new oxyheme models—hydrogen bonding(H-bonding)and covalent-bond axial ligand.Hbonding extensively exists in protein environment and is crucial for the oxyheme functions.Covalent-bond axial ligand could change the orientation,basicity of proximal histidine and thus charge donation to the iron,which finally tuning the Fe-O_(2) bond strength.These structural modifications of oxyheme pocket could control and/or change the dioxygen motions and dynamic disorder,providing new insights into the electronic and geometric structures of Fe-O_(2) bond.In addition,our previous experience on oxyhemes studies indicated that dioxygen motions are strongly related to the thermal situation.Hence the temperature-dependent single-crystal characterization,which will give vivo pictures on the dioxygen dynamic motions,is necessary.The new research will shed light on the studies of the nature of Fe-O_(2) bond,which will enrich the bioinorganic theories and are important for the biologically functional material research.

关 键 词：氧 血红素 铁 电子结构 穆斯堡尔谱 

分 类 号：TB391[一般工业技术—材料科学与工程]