Redox Cofactor Diversity in Enzymatic Superfamilies

项目摘要 大自然已经掌握了利用生物可利用的金属实现惊人的化学变化的能力， 通过将它们与不同的蛋白质折叠和独特的协调环境相结合。通过组装 金属蛋白和金属酶，自然界在化学转化中实现了显著的多样性 在调整铁等金属离子的新生属性时，通过产生还可进一步修改的 氧化还原活性辅因子，如铁-硫簇和结合在血红素辅因子中的铁。为了实现这种多样性， 阐述了特定的蛋白质支架和铁-硫簇和/或血红素基团的排列 在广泛的基础上，给我们提供了不同的化学-其中大部分，酶学和生物无机领域是 时至今日仍在探索。波士顿大学埃利奥特小组正在进行的两个由NIGMS资助的研究领域 主要有：(1)对大分子的结构-功能关系提出质疑， 成千上万的反应被认为是由数以千计的不同成员催化的 在ARE中，通过研究ARE超家族中发现的铁硫簇的氧化还原特性；以及 (2)测试关于结构和化学多样性的假设，这些假设是在含血红素的SO- 革兰氏阴性微生物体内发现的细菌细胞色素C过氧化物酶(BCCP)超家族。 通过这两个相关项目，这两个项目构成了当前R35提案的背景， 金属蛋白的结构、功能和氧化还原化学通过以下几个方面进行研究 电化学法、生物物理学方法、生物信息学方法和结构方法。ARE的机械性细节 超家族仍然即将到来，在那里已经提出了许多铁-硫团簇的新状态；在这里，我们 将使我们的电化学透镜作用于这些状态的性质，以便理解 它们的生成和相互转化的热力学和动力学。关于bccp超级家族， 我们最近已经证明，这个超家族的酶的新的反应性形式可以通过 看看过去20年来接受过检查的典型家庭成员。在这里我们 建议审查其他建议从事硫磺转化的新家庭成员 微生物群和人类健康。总之，这些研究结合了我们对生物信息学和 生物物理化学，探索自然界氧化还原酶的多样性，不仅揭示了 这些非凡的催化剂的化学，但自然如何掌握所需的反应性与正确的 金属辅因子。

PROJECT ABSTRACT Nature has mastered the ability to use bioavailable metals to achieve spectacular transformations of chemistry, by combining them with diverse protein folds, and unique coordination environments. Through the assembly of metalloproteins and metalloenzymes, Nature has achieved remarkable diversity in chemical transformations and in tuning the nascent properties of metal ions such as iron, through generating yet-further-modifiable redox-active cofactors, like iron-sulfur clusters and iron bound in heme cofactors. To achieve that diversity, specific protein scaffolds and arrangements of iron-sulfur clusters, and/or heme groups have been elaborated upon extensively, giving us diverse chemistry — much of which, the fields of enzymology and bioinorganic are still discovering today. Two NIGMS funded research areas ongoing in the Elliott Group at Boston University are (1) Query the structure-function relationships of the vast, “AdoMet Radical Enzyme (ARE) superfamily”, where tens of thousands of reactions are thought to be catalyzed by hundres of thousands of distinct members of the ARE, through the study of the redox traits of the iron sulfur clusters found in the ARE superfamily; and (2) Test hypotheses about structural and chemical diversity found with heme containing enzymes of the so- called “bacterial cytochrome c peroxidase (bCCP) superfamily” found within gram negative micro-organisms. Through these two related projects, which form the background of the current R35 proposal, the diversity of structures, function and redox chemistries of metalloproteins are examined through a combination of electrochemical, biophysical, bioinformatic, and structural approaches. The mechanistic details of the ARE superfamily are still forthcoming, where many novel states of iron-sulfur clusters have been proposed; here we will bring our electrochemical lens to bear upon the nature of those states, in order to understand the thermodynamics and kinetics of their generation and inter-conversion. With respect to the bCCP superfamily, we have recently demonstrated that novel forms of reactivity of enzymes of this superfamily can be found by looking beyond the canonical family members that have been examined for the past 20 years. Here we propose to examine other new family members that are suggested to engage in sulfur-conversions relevant to the microbiome and to human health. Together, these studies marry our interests in bioinformatics and biophysical chemistry, to probe the diversity of nature's redox enzymes, revealing not only what is possible in the chemistry of these remarkable catalysts, but how nature masters the desired reactivity with the correct metallocofactor.