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来实现壮观转变的能力 通过将它们与不同的蛋白质折叠和独特的协调结合， 环境.通过金属蛋白和金属酶的组装，大自然已经 在化学转化和调整新生性质方面取得了显著的多样性， 通过产生可进一步修饰的氧化还原活性辅因子，例如铁等金属离子 铁硫簇和铁结合在血红素辅因子中。为了实现这种多样性，特定的蛋白质 铁硫簇和/或血红素基团的支架和排列已经被详细阐述 广泛地，给我们不同的化学-其中大部分，酶学和 生物无机物仍在探索中。两个NIGMS资助的研究领域正在埃利奥特 波士顿大学的一个研究小组的工作是（1）质疑大量的“蛋白质”的结构-功能关系， 自由基酶（ARE）超家族”，其中成千上万的反应被认为是 通过研究，成千上万的不同成员的ARE， ARE超家族中发现的铁硫簇的氧化还原特性;（2）测试关于 结构和化学多样性发现与血红素含有酶的所谓“细菌 细胞色素c过氧化物酶（bCCP）超家族”在革兰氏阴性微生物中发现。 通过这两个相关的项目，它们构成了当前R35提案的背景， 金属蛋白质的结构、功能和氧化还原化学的多样性通过一个 电化学、生物物理学、生物信息学和结构方法的组合。的 ARE超家族的机制细节仍然即将到来，其中许多新的铁状态 硫簇已经提出;在这里，我们将把我们的电化学透镜承担在 这些状态的性质，以了解它们产生的热力学和动力学 和相互转换。关于bCCP超家族，我们最近已经证明， 该超家族的酶的反应性的新形式可以通过超越酶的活性而发现。 在过去的20年里，这些典型的家庭成员已经被检查过了。在此，我们建议 检查其他新的家庭成员，建议从事硫转化相关， 对微生物和人类健康的影响。总之，这些研究结合了我们的兴趣， 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催化剂的化学可能性， 掌握与正确金属辅因子的所需反应性。

Project Summary 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 hundreds 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 relevan 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.