Structure, Spectra, and Roles of Metal and Active Site in HNO Heme Protein Comple

描述（申请人提供）：HNO在许多生物过程中具有独特的作用，如血管舒张，酶活性调节和神经功能调节。其药理作用包括增强肾缺血/再灌注时的细胞氧化应激、血脑屏障破坏和中性粒细胞浸润。与同类信号分子NO相比，HNO所表现出的优先血管扩张作用使HNO供体成为一种潜在的新型血管扩张剂和心力衰竭治疗药物。HNO的许多生物学效应与血红素蛋白和其他金属蛋白有关。HNO蛋白复合物的结构信息是了解HNO生理和药理功能的必要条件。然而，目前还没有发现HNO蛋白复合物的晶体结构。本工作的总体目标是利用高精度量子力学方法研究唯一分离的HNO蛋白复合物MbHNO （Mb =肌红蛋白）及其相关血红素蛋白复合物和HNO金属复合物的结构、特征光谱数据、金属和活性位点的作用。第一个具体目标是建立量子化学方法，能够准确重现HNO金属配合物（包括血红素蛋白模型系统）中广泛的实验NMR位移和振动频率，并确定金属和配体集对HNO稳定性和光谱的影响。第二个具体目标是全面研究MbHNO可能的活性位点模型，包括HNO部分不同的氢键模式、附近残基的不同尺度和不同的配体取向。将确定MbHNO的几何结构，该几何结构在定量上与实验核磁共振、振动和x射线吸收光谱数据一致。HNO与活性位点附近残基的相互作用对MbHNO几何结构、HNO稳定能和光谱性质的影响，以及与MbNO、MbO2和RNO （R =烷烃和芳烃）血红素蛋白复合物的比较，将被检验以提高我们对活性位点功能作用的理解。结果将提供HNO与蛋白质和模型中金属中心相互作用的结构、光谱和功能方面的有用细节，这将有助于未来涉及HNO的健康、疾病和治疗治疗的研究。公共卫生相关性：该项目将提供HNO与蛋白质中金属中心相互作用的结构、光谱和功能方面的有用细节。由于HNO参与与健康相关的广泛生理过程，具有广泛的药理作用，并为心力衰竭和中风等疾病提供了有希望的新治疗方法，本项目的结果将有助于未来涉及HNO的健康，疾病和治疗治疗的研究。

DESCRIPTION (provided by applicant): HNO has distinctive roles in many biological processes, such as vascular relaxation, enzyme activity regulation, and neurological function regulation. Its pharmacological effects include enhanced cell oxidative stress, blood-brain barrier disruption and neutrophil infiltration during renal ischemia/reperfusion. The preferential vasodilative effect exhibited by HNO compared to its sibling signaling molecule NO makes HNO donors a potential new class of vasodilators and heart failure treatments. Many of the biological effects of HNO are involved with heme proteins and other metalloproteins. Structural information of the HNO protein complexes is necessary for understanding the physiological and pharmacological functions of HNO. However, there are currently no crystal structures of HNO protein complexes. The overall objective of this work is to investigate the structure, characteristic spectroscopic data, and the roles of metal and active site in the only isolated HNO protein complex, MbHNO (Mb = myoglobin), and related heme protein complexes and HNO metal complexes using high accuracy quantum mechanics methods. The first specific aim is to establish quantum chemical methods that can accurately reproduce the broad range of experimental NMR shifts and vibrational frequencies seen in HNO metal complexes, including heme protein model systems, and determine the effects of metal and ligand set on the HNO stability and spectra. The second specific aim is to conduct a comprehensive investigation of possible active site models of MbHNO, with different hydrogen bonding modes for the HNO moiety, different scales of nearby residues, and different ligand orientations. A geometric structure that quantitatively agrees with experimental NMR, vibrational, and X-ray absorption spectroscopic data will be determined for MbHNO. Effects of HNO interactions with nearby residues in the active site on the MbHNO geometry, HNO stabilization energy, and spectroscopic properties, as well as comparisons with MbNO, MbO2, and RNO (R = alkane and arene) heme protein complexes will be examined to improve our understanding of the functional role of the active site. Results will provide useful details of the structural, spectral and functional aspects of HNO interactions with metal centers in proteins and models, which will assist in future studies of health, diseases, and therapeutic treatments involving HNO. PUBLIC HEALTH RELEVANCE: This project will provide useful details of structural, spectral and functional aspects of HNO interactions with metal centers in proteins. Since HNO participates in a broad range of physiological processes related to health, has extensive pharmacological effects, and offers a promising new treatment for diseases such as heart failure and stroke, results from this project will assist future studies of health, diseases, and therapeutic treatments involving HNO.