A Biosynthetic Approach Toward Biomimetic Studies of Metalloproteins Involved in Long-range Electron Transfer

这个无机、生物无机和有机金属化学项目的奖项支持Lu Yi教授和伊利诺伊大学厄巴纳-香槟分校的研究，通过应用生物学上的两种新技术，即表达蛋白连接（EPL）和环导向突变（LDM），更深入地了解金属离子中心（如CuA和[Fe2S2]）的电子转移（ET）的配位化学和生物学作用。EPL将引入非天然氨基酸进行同位结构取代，从而可以更精确地阐明azurin中CuA中心一级配位球和二级配位球残基的作用，从而确定a) Cu-Cu键距离和“金刚石核”角等几何结构；B)电子结构，如电子离域的程度；c)功能性质，如中心的还原电位和电子转移速率。LDM将用于将三个突出的ET中心（蓝铜，CuA和[Fe2S2]中心）放置在相同的azurin蛋白质框架中，从而可以直接比较它们的结构和功能特性，例如电子离域的程度和ET效率。从该研究中获得的见解将允许设计具有可调氧化还原和电子转移特性的金属结合位点，这对生物呼吸（在细胞色素氧化酶的情况下）和全球氮循环（在n2o还原酶的情况下）非常重要。从生物学中引入两项新技术也使基础配位化学得到了发展。将开发讲座和实验模块（包括测验），将多学科研究整合到研究生和本科课程教学中。一门名为“日常生活的化学和生物学”的课程将利用这项研究的材料得到加强。为了扩大代表性不足的群体的参与，PI将在各机构和夏令营举办研讨会，并参加暑期研究机会项目。

This award in the Inorganic, Bioinorganic and Organometallic Chemistry program supports research by Professor Yi Lu and the University of Illinois at Urbana-Champaign to gain a deeper understanding of the coordination chemistry and biological role of electron transfer (ET) at metal ion centers such as CuA and [Fe2S2] in proteins by applying two new techniques from biology, i.e. expressed protein ligation (EPL) and loop-directed mutagenesis (LDM). Unnatural amino acids will be introduced by EPL in order to make isostructural substitutions that will make it possible to elucidate the roles of the residues in the primary and secondary coordination sphere of the CuA center in azurin more precisely in determining a) geometric structures, such as the Cu-Cu bond distance and the "diamond core" angle; b) electronic structure, such as the extent of electron delocalization and c) functional properties, such as the reduction potentials and electron transfer rates of the center. LDM will be used to place three prominent ET centers (blue copper, CuA and [Fe2S2] centers) in the same protein framework of azurin, allowing a direct comparison of their structural and functional properties, such as extent of electron delocalization and ET efficiency. Insights obtained from the study will allow the design of metal-binding sites with tunable redox and electron-transfer properties, which is important to biological respiration (in the case of cytochrome oxidase) and the global nitrogen cycle (in the case of N2O-reductase). Introducing two new techniques from biology also allows the advancement of basic coordination chemistry. Lecture and lab modules (including quizzes) will be developed to integrate multidisciplinary research into graduate and undergraduate course instruction. A course called "Chemistry and Biology of Everyday Life" will be enhanced using materials from this research. To broaden participation of underrepresented groups, the PI will give seminars at institutions and summer camps, and participate in summer research opportunity programs.