Structural Studies on Nitric Oxide Synthase

项目描述（申请人提供）：本项目的长期目标是研究一氧化氮合酶（NOS）的结构-功能关系。NOS是负责将精氨酸氧化为一氧化氮（NO）的酶。近年来，一氧化氮已被公认为参与神经、免疫和心血管系统的主要生理信使分子。由于NO作为调控分子的效力和重要性，NOS是一种受到严格控制的复杂酶。该酶由血红素结构域和FMN/FAD结构域组成，前者是精氨酸实际氧化发生的地方，后者用于将电子从NADPH传送到血红素结构域。在血红素和黄素结构域之间是一个连接体，它与另一个调节分子钙调蛋白结合。除了血红素、FMN和FAD外，NOS还含有另一种辅助因子——四氢生物蝶呤。我们的实验室已经解决了所有3种哺乳动物NOS异构体的催化血红素域的晶体结构。这为利用基于结构的方法开发异构体选择性抑制剂开辟了道路。结合晶体学，体内/体外测试，计算化学和合成化学将用于开发新的异构体选择性抑制剂。此外，新技术将被纳入NOS动力学和电子转移问题。特别是利用高场核磁共振波谱研究hoio-NOS中的畴相互作用和激光闪光光解方法研究电子转移过程。

DESCRIPTION (provided by applicant): The long range goal of this project is to study structure-function relationships in nitric oxide synthase (NOS). NOS is the enzyme responsible for the oxidation of arginine to nitric oxide (NO). In recent years, nitric oxide has been recognized as a major physiological messenger molecule involved in the nervous, immune, and cardiovascular systems. Owing to the potency and importance of NO as a regulatory molecule, NOS is a complex enzyme under stringent control. The enzyme consists of a heme domain, where the actual oxidation of arginine occurs and an FMN/FAD domain that serves to shuttle electrons from NADPH to the heme domain. Between the heme and flavin domains is a linker that binds another regulatory molecule, calmodulin. In addition to heme, FMN, and FAD, NOS contains yet another cofactor, tetrahydrobiopterin. Our lab has solved the crystal structure of the catalytic heme domain of all 3 mammalian NOS isoforms. This has opened the way for using structure-based approaches for developing isoform-selective selective inhibitors. A combination of crystallography, in vivo/in vitro testing, computational chemistry, and synthetic chemistry will be used to develop novel isoform-selective inhibitors. In addition, new technologies will be incorporated into the problem of NOS dynamics and electron transfer. In particular, is the use of high field NMR spectroscopy to study domain interactions in hoio-NOS and laser flash photolysis methods for studying electron transfer processes.