PHOTO-INDUCED TRANSIENTS OF HEMOPROTEIN-LIGAND COMPLEXES

肌红蛋白与氧等双原子配体的相互作用模式， 一氧化碳和一氧化氮用环境和低温探测 温度光解氧气在生物学中起着重要作用， 有效保存能量所需的氧化代谢， 戒毒一氧化碳和一氧化氮是众所周知的空气 与血红素蛋白结合的污染物。一氧化氮-血红素蛋白 络合物经常被观察到作为中间体/副产物 氮致癌物的代谢和固氮作用。因此，在本发明中， 了解肌红蛋白与这些双原子相互作用的模式 配体在阐明其作用机制方面具有重要意义。 生物氧化抹香鲸和牛肌红蛋白，它们的位置- 定向突变体和钴取代的衍生物。可见 和红外（IR）瞬态动力学研究进行了 肌红蛋白-配体复合物在亚皮科至毫秒内的光解 时间尺度，以便分析成对和双分子复合 过程，并确定成对和量子产率的光解。的 肌红蛋白中结合配体的几何形状将由周围环境确定 温度超快/偏振红外或低温单晶 电子顺磁共振（BPR）技术。电子和 肌红蛋白初级光解态的立体化学结构， 钴-肌红蛋白及其定点突变体和释放的配体 将通过低温IR、EPR和共振拉曼来表征 谱定点突变对结构的影响， 将评估肌红蛋白的反应性，以确定配体 亲和力由分子的立体化学和电子性质控制 远端结构

Modes of interaction of myoglobin with diatomic ligands like oxygen, carbon monoxide, and nitric oxide are probed with ambient and cryogenic temperature photolysis. Oxygen plays fundamental roles in the biological oxidative metabolism required for efficient conservation of energy and drug detoxification. Carbon monoxide and nitric oxide are well-known air pollutants which bind with hemoproteins. Nitric oxide-hemoprotein complexes are frequently observed as intermediates/byproducts of metabolism of nitrogeneous carcinogens and nitrogen fixation. Thus, understanding of the mode of interaction of myoglobin with these diatomic ligands is of vital importance in elucidation of the mechanism of biological oxidation. Sperm whale and bovine myoglobins, their site- directed mutants, and cobalt-substituted derivatives are prepared. Visible and infrared (IR) transient kinetic studies are Carried out for the photolysis of myoglobin-ligand complexes in sub-pico to millisecond timescales in order to analyze geminate and bimolecular recombination processes and to determine geminate and quantum yields of photolysis. The geometry of the bound ligands in myoglobin will be determined by ambient temperature ultrafast/polarized IR or low temperature single crystal electron paramagnetic resonance (BPR) techniques. Electronic and stereochemical structures of primary photolyzed states of myoglobin, cobalt-myoglobin and their site-directed mutants and the liberated ligands will be characterized by low temperature IR, EPR, and resonance Raman spectroscopy. The effects of site-directed mutations on structure and reactivity of myoglobin will be assessed in order to determine how ligand affinity is controlled by stereochemical and electronic properties of the distal structure.