Crosstalk of NO, O2, and H2S at the [4Fe4S] interface: exploring the reactivity with biomimetic model complexes

越来越多的小的，可自由扩散的气体信号分子，称为“gasotransmitters”，被认为在动物，植物和细菌的生物信号中发挥关键作用。个体气体递质信号通路的广泛重叠导致对人类健康具有影响的累积效应。气体递质一氧化氮（NO）的生物活性直接受到其他小的氧、氮和硫基生物活性气体分子的影响。我的高度多学科的研究计划的长期目标是探索在铁硫（FeS）簇金属蛋白中心的接口与其他gasotransmitter物种的NO的特定反应。 本研究主要包括三个短期目标（SO）。在SO 1中，我们将寻求探索FeS簇与NO和O2反应性副产物的反应。在生物学中，这些分子是触发和指导针对亚硝化应激的保护性反应的活性剂，所述亚硝化应激由专门的FeS簇蛋白介导。我们将利用人工合成的小分子配体和卷曲螺旋人工合成的蛋白质配体，设计并合成一系列仿生模型FeS簇合物。然后，我们将使用这些来探索氧化环境对NO反应性的影响，并开发出一种强大的光谱方法来表征关键的反应中间体。在SO2中，我们将探索铁硫簇合物界面处NO和H2S反应性的交叉点。与NO反应后从FeS簇中损失的硫化物的命运已被牵连为生物小分子过硫化物物种和H2S的来源。因此，我们有兴趣在探索生物相关的硫基信号分子，包括H2S，从NO和FeS簇的反应的控制生成。我们将建立在SO 1中开发的方法，适用于捕获反应中间体和控制硫物质的形成。在SO 3中，我们将使用FeS簇支架作为产生新的假定气体发射器HSNO的基础。我们寻求开发一种从头蛋白质系统，该系统专门设计用于促进S-N键的形成，随后在受控条件下释放SNO-单元，并且可通过蛋白质修饰（如糖基化）靶向。HSNO已被确定为一种新的气体递质，了解它的产生将促进对它在生物学中作用的理解。 影响：该研究计划将使用尖端的合成和分析方法来提高生物相关反应性小分子的科学知识的现状。将提供新的工具来检查这些非常不稳定和难以研究的分子。在该计划中接受培训的学生将受益于高度多学科的培训，其中合成无机，生物无机和分析化学将用于实现新的科学发现。

A growing number of small, freely-diffusible gaseous signaling molecules, termed `gasotransmitters,' are understood to play key roles in biological signaling in animals, plants, and bacteria. The extensive overlap in individual gasotransmitter signaling pathways leads to cumulative effects that have implications for human health. The biological activity of the gasotransmitter nitric oxide (NO) is directly influenced in its activity by other small oxygen-, nitrogen-, and sulfur-based bioactive gas molecules. The long term objective of my highly multidisciplinary research program is to explore the specific reactivity of NO with other gasotransmitter species at the interface of iron-sulfur (FeS) cluster metalloprotein centres. This research progam consists of three main short term objectives (SOs). In SO1, we will seek to explore the reaction of FeS clusters with byproducts of NO and O2 reactivity. In biology, these molecules are active agents in triggering and directing a protective response against nitrosative stress mediated by specialized FeS cluster proteins. We will design and synthesize a series of biomimetic model FeS cluster complexes using synthetic small molecule ligands and coiled coil synthetic protein ligands. We will then use these to explore the effect of an oxidative environment on NO reactivity, and develop a robust spectroscopic methodology to characterize key reaction intermediates. In SO2, we will explore the intersection of NO and H2S reactivity at the interface of iron sulfur clusters. The fate of sulfides lost from FeS clusters following reaction with NO has been implicated as a source of biological small molecule persulfide species and H2S. We are therefore interested in exploring the controlled generation of biologically relevant sulfur-based signalling molecules, including H2S, from the reaction of NO and FeS clusters. We will build on methodologies developed in SO1, adapted towards trapping reaction intermediates and control of sulfur species formation. In SO3, we will use the FeS cluster scaffold as a basis for generating the novel putative gasotransmitter HSNO. We seek to develop a de novo protein system designed specifically to promote the formation of an S-N bond with subsequent release of the SNO- unit under controlled conditions and targetable via protein modification such as glycosylation. HSNO has been identified as a new gasotransmitter and understanding its generation would advance understanding of its role in biology. Impacts: The research program will enhance the current state of scientific knowledge of biologically-relevant reactive small molecules using cutting-edge synthetic and analytical approaches. New tools will be provided to examine these very unstable and difficult to study molecules. Students trained in this program will benefit from a highly multidisciplinary training where synthetic inorganic, bioinorganic and analytical chemistries will be utilized to achieve new scientific findings.