Mechanisms of electron transfer in nitric oxide synthases

一氧化氮合酶中的电子转移机制

基本信息

批准号：
8232160
负责人：
Changjian Feng
金额：
$ 33.22万
依托单位：
UNIVERSITY OF NEW MEXICO HEALTH SCIS CTR
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-08-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8232160
关键词：
Academic Research Enhancement Awards Active Sites Address Biological Biological Process Calmodulin Catalysis Clinical Treatment Complex Cytotoxin Data Development Dioxygen Disease Docking Electron Spin Resonance Spectroscopy Electron Transport Enzymes Family Flavin Mononucleotide Goals Guidelines Heme Hemeproteins Lasers Length Ligands Malignant Neoplasms Molecular Mutation Nitric Oxide Nitric Oxide Synthase Nitric Oxide Synthase Type I Outcome Oxygenases Pathway interactions Pharmaceutical Preparations Pharmacologic Substance Physiologic pulse Process Production Protein Isoforms Proteins Regulation Relative (related person)Research Role Scheme Signaling Molecule Site Site-Directed Mutagenesis Stroke Structure Substrate Interaction Testing Therapeutic Intervention Training Vasodilation base biomedical scientist design deviant effective therapy enzyme activity flash photolysis improved inhibitor/antagonist innovation insight neurotransmission oxidation programs

项目摘要

Nitric oxide synthase (NOS), a flavo-hemoprotein, tightly regulates nitric oxide (NO) synthesis and thereby its dual biological activities as a key signaling molecule for vasodilatation and neurotransmission at low concentrations, and also as a defensive cytotoxin at higher concentrations. Three NOS isoforms, iNOS, eNOS and nNOS (inducible, endothelial, and neuronal NOS), achieve their key biological functions by tight regulation of interdomain electron transfer (IET) process via interdomain interactions. Our long-term goal is to determine the molecular mechanism of NOS enzyme catalysis, including how the interdomain interactions modulate the catalytically relevant IET processes and the NOS enzyme function. In this project we will focus on investigating important roles of the FMN domain docking to the heme domain in regulating the NOS isoform function. An exciting recent development in the NOS enzymes is the discovery of importance of the interdomain FMN-heme interactions for modulating reactivity and structure of the catalytic heme active site. The recent findings raise two new important mechanistic questions that must be addressed to understand NOS regulation mechanism: 1) what specific interdomain interactions govern and facilitate the productive docking of the FMN domain to the heme domain? 2) how can the FMN domain docking, in addition to controlling the catalytically essential FMN-heme IET, modulate reactivity of the heme active site? Our two synergistic and complementary Aims are designed to directly address these important questions. We will employ an integrated program of pulsed electron paramagnetic resonance, laser flash photolysis and mutational studies. In the absence of a structure of full-length mammalian NOS, the combined approach is highly appropriate for the proposed study. This project seeks to address fundamental questions relating to the NOS enzymes. Our study will identify key structural determinants in controlling NOS isoform activity by modulating the alignment of the FMN and heme domains. The new information could facilitate bio-rational development of new selective activators or inhibitors for these clinically important enzymes, in order to provide better therapeutic interventions. In accordance with the guideline of the R15 program we will continue to train our 21st century biomedical scientists by this multi-disciplinary project.

一氧化氮合酶 (NOS) 是一种黄素血红素蛋白，严格调节一氧化氮 (NO) 的合成，从而其作为血管舒张和神经传递的关键信号分子的双重生物活性浓度，并且在较高浓度下也作为防御性细胞毒素。三种 NOS 异构体：iNOS、eNOS 和 nNOS（诱导型、内皮型和神经元型 NOS），通过严格调控实现其关键生物学功能通过域间相互作用的域间电子转移（IET）过程。我们的长期目标是确定 NOS酶催化的分子机制，包括域间相互作用如何调节催化相关的 IET 过程和 NOS 酶功能。在这个项目中，我们将重点研究 FMN 结构域与血红素对接的重要作用调节 NOS 亚型功能的结构域。 NOS 酶的一项令人兴奋的最新进展是发现域间 FMN-血红素相互作用对于调节反应性和结构的重要性催化血红素活性位点。最近的发现提出了两个新的重要机制问题，必须予以解决旨在理解 NOS 调节机制：1）哪些特定的域间相互作用控制和促进 FMN 结构域与血红素结构域的高效对接？ 2）FMN域如何对接，除了控制催化必需的 FMN-血红素 IET 之外，还调节血红素的反应性活跃站点？我们的两个协同和互补的目标旨在直接解决这些重要问题问题。我们将采用脉冲电子顺磁共振、激光闪光的综合方案光解和突变研究。在缺乏全长哺乳动物 NOS 结构的情况下，组合方法非常适合拟议的研究。该项目旨在解决与 NOS 酶相关的基本问题。我们的研究将确定通过调节 FMN 和 FMN 的排列来控制 NOS 亚型活性的关键结构决定因素血红素域。新信息可以促进新选择性激活剂的生物合理开发或这些临床上重要的酶的抑制剂，以便提供更好的治疗干预措施。在按照R15计划的指导方针，我们将继续培养我们的21世纪生物医学人才科学家们通过这个多学科项目。