PHOTO-INDUCED TRANSIENTS OF HEMOPROTEIN-LIGAND COMPLEXES

光诱导的血蛋白-配体复合物的瞬变

• 批准号: 6240539
• 负责人: TAKASHI YONETANI
• 金额: $ 11.72万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-01 至 1998-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6240539
• 关键词: Raman spectrometry; carbon monoxide; chemical models; cryoscience; electron spin resonance spectroscopy; electronic spectra; hemoprotein structure; infrared spectrometry; intermolecular interaction; ligands; myoglobin; nitric oxide; oxidation reduction reaction; oxygen; photochemistry; photolysis; site directed mutagenesis; stereochemistry

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.

肌红蛋白与氧气（如氧气）的相互作用模式， 用环境和低温探测一氧化碳和一氧化氮 温度光解。氧气在生物学中起着基本作用 有效保存能量和 药物排毒。一氧化碳和一氧化氮是众所周知的空气 与血红蛋白结合的污染物。一氧化氮血蛋白 复合物经常被视为中间体/副产品 硝化致癌物和氮固定的代谢。因此， 了解肌红蛋白与这些双原子的相互作用方式 配体对于阐明机制至关重要 生物氧化。 Sperm Whale和Bovine myoglobins，他们的现场 - 制备定向突变体和钴取代的衍生物。可见的 和红外（IR）瞬时动力学研究进行 肌红蛋白配体复合物的光解至毫秒至毫秒 为了分析Geminate和双分子重组的时间表 过程并确定光解的颗粒和量子产率。这 肌红蛋白中结合配体的几何形状将由环境确定 温度超快/极化IR或低温单晶 电子顺磁共振（BPR）技术。电子和 肌球蛋白原代光解状态的立体化学结构， 钴 - 叶绿素及其位置指导的突变体及其释放的配体 将以低温IR，EPR和共振拉曼为特征 光谱法。位置突变对结构和结构的影响 将评估肌红蛋白的反应性，以确定配体如何 亲和力由立体化学和电子特性控制 远端结构。