Structural Biology of Gaseous Messenger Signaling

描述（由申请人提供）：一氧化氮（NO）、一氧化碳（CO）和分子氧（O2）是哺乳动物中的三种关键气体信使。虽然在阐明这些分子生物合成的机制方面取得了重大进展，但对它们如何传递信号以触发生理反应知之甚少。NO通过其血红素蛋白受体可溶性鸟苷酸环化酶（sGC）介导其生理作用。尽管经过了三十年的研究，但NO与sGC结合如何激活第二信使（cGMP）产生的结构基础尚不清楚。我们制定了创新战略，以深入了解这一过程。这包括我们发现了一个新的细菌NO传感器（SONO）家族，该家族与sGC的传感器结构域具有显着的序列同一性。虽然SONO的信号在20亿年的进化中保持不变，但其功能与cGMP生物合成无关。我们已经确定的SONO-蛋白质相互作用使我们能够构建一个挑衅性的假设，即NO传感器是一个混杂的分子开关，能够通过一组有限的结构变化触发功能无关的信号传导事件。为了检验这一假设，设计了四个具体目标：目标1。NO和CO活化的SONO的结构是什么？目的2：人sGC的血红素和NO非依赖性信号传导的结构基础是什么？目的3：NO和激活剂结合如何与sGC催化偶联？目的4：SONO介导人类病原体趋化性的分子机制是什么？这项研究将为气体信使信号传导机制提供新的见解。它还将为旨在制定心血管疾病治疗干预措施的合理战略铺平道路。公共卫生相关性：一氧化氮是一种由血管细胞产生的气体，它有多种功能，其中之一就是能够将男性的性兴奋转化为勃起。该提案旨在了解一氧化氮如何在健康和疾病状态下发挥作用。

DESCRIPTION (provided by applicant): Nitric oxide (NO), carbon monoxide (CO), and molecular oxygen (O2) are three key gaseous messengers in mammals. Although significant advances have been made in elucidating the mechanisms by which these molecules are biosynthesized, very little is known about how they transduce signals to trigger a physiological response. NO mediates its physiological actions via its heme protein receptor, soluble guanylyl cyclase (sGC). Despite three decades of research, the structural basis of how NO binding to sGC activates second messenger (cGMP) production is not understood. We have devised innovative strategies to gain insights into this process. This includes our discovery of a novel family of bacterial NO sensors (SONO) that share remarkable sequence identity with the sensor domain of sGC. Although the signal for SONO has remained unchanged during two billion years of evolution, its function is unrelated to cGMP biosynthesis. The SONO-protein interactions we have identified has allowed us to frame the provocative hypothesis that the NO sensor is a promiscuous molecular switch capable of triggering functionally unrelated signaling events via a limited set of structural changes. Four specific aims have been designed to test this hypothesis: Aim 1. What is the structure of NO- and CO-activated SONO? Aim 2: What are the structural bases of heme- and NO-independent signaling by human sGC? Aim 3: How is NO and activator binding coupled to sGC catalysis? Aim 4: What is the molecular mechanism by which SONO mediates chemotaxis in human pathogens? The proposed research will provide novel insights into mechanisms of gaseous messenger signaling. It will also pave the way for rational strategies aimed at developing therapeutic interventions for cardiovascular diseases. PUBLIC HEALTH RELEVANCE: Among the several functions of nitric oxide - a gas produced by the cells lining our blood vessels - is its ability to convert sexual excitement into erections in males. This proposal is aimed at understanding how nitric oxide works in healthy and disease states.