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，被称为“气体传递器”，被认为在动物、植物和细菌的生物信号中发挥关键作用。单个气体递质信号通路的广泛重叠导致了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氧、氮、硫基生物活性气体小分子的影响。我的高度多学科研究计划的长期目标是探索NO与铁-硫(FeS)簇状金属蛋白中心界面上其他气体递质物种的特异性反应。这项研究包括三个主要短期目标(SOS)。在SO1中，我们将探索FeS团簇与NO和O2反应的副产物的反应。在生物学上，这些分子是由特殊的FeS簇蛋白介导的触发和指导针对亚硝化应激的保护性反应的活性物质。我们将利用合成的小分子配体和盘绕合成的蛋白质配体，设计并合成一系列仿生模型FeS簇合物。然后，我们将使用这些方法来探索氧化环境对NO反应性的影响，并开发一种强大的光谱方法来表征关键的反应中间产物。在SO2中，我们将探索NO和H_2S在铁硫团簇界面上的反应活性的交集。FeS团簇中硫化物与NO反应后的去向被认为是生物小分子过硫化物物种和H_2S的来源之一。因此，我们有兴趣探索从NO和FeS团簇的反应中控制产生生物相关的硫基信号分子，包括硫化氢。我们将建立在SO1中开发的方法，适用于捕获反应中间体和控制硫物种的形成。在SO3中，我们将使用FeS团簇支架作为产生新型假定气体发射器HSNO的基础。我们寻求开发一种从头蛋白系统，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-单位，并可通过糖基化等蛋白质修饰来靶向。HSNO已被确定为一种新的气体传递器，了解它的产生将促进对其在生物学中作用的理解。影响：该研究计划将利用尖端的合成和分析方法，加强与生物相关的活性小分子的科学知识的现状。将提供新的工具来研究这些非常不稳定和难以研究的分子。在这个项目中接受培训的学生将从高度多学科的培训中受益，其中将利用合成无机、生物无机和分析化学来实现新的科学发现。

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.