HIGH RESOLUTION SPECTROSCOPY OF HEME PROTEINS

血红素蛋白的高分辨率光谱

• 批准号: 6240535
• 负责人: Jane Marie Vanderkooi
• 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/6240535
• 关键词: chromophore; conformation; cryoscience; cytochromes; electronic spectra; hemoprotein structure; intermolecular interaction; laser spectrometry; myoglobin; photochemistry; porphyrins

The optical spectra of chromophores in proteins are broad due to large inhomogeneous broadening under the usual conditions of measurement. Using high resolution laser spectroscopy at cryogenic temperatures to photoselect among conformational substates, resolved spectra are obtained. We have shown that in metal free and metal substituted heme proteins the fluorescence line narrowing and hole burning spectra reveal details of the porphyrin electronic and vibrational structural features and which can be used to compare the vibrational structural features of both the ground and excited state molecules. In the proposed work we will study porphyrin interactions with the polypeptide chain using cytochrome c and myoglobin. The specific aims are to: l. Examine parameters of the heme pocket that determine the porphyrin spectral properties. Cytochrome c and myoglobin from various sources will be selected where specific amino acid changes in the heme pocket allow us to ask whether particular amino acids affect the spectral characteristics. Distribution in the electronic energies will be related to the distribution of conformational substates. 2. Investigate how changes in the spectra can be used to detect changes in the peptide chain, such as those induced by complex formation (as for cyt c binding to CCP) or by altering medium conditions. 3. Examine how the protein polypeptide chain is affected by photoreactions of the porphyrin and consider how the chain influences rates of a photo- tautomerization reaction. As a monitor occurring in the heme pocket we will use high resolution absorption techniques of fluorescence line-narrowing, hole burning and infrared spectroscopies. The aims will be addressed by systematically comparing different metal derivatives, different porphyrins and different proteins and by altering experimental conditions.

蛋白质中发色团的光谱由于较大 在通常的测量条件下，不均匀的拓宽。使用 高分辨率激光光谱在低温温度下 在构象取代物，分辨光谱中的摄影选择。 我们已经表明，在金属和金属取代的血红素蛋白中 荧光线变窄和孔燃烧光谱揭示了细节 卟啉电子和振动结构特征，可以是 用于比较地面和地面的振动结构特征 激发状态分子。在拟议的工作中，我们将研究卟啉 使用细胞色素C和肌红蛋白与多肽链相互作用。 具体目的是： l。检查确定卟啉的血红素袋的参数 光谱特性。来自各种来源的细胞色素C和肌红蛋白将 在血红素口袋中特定氨基酸变化的地方选择可以让我们 询问特定的氨基酸是否影响光谱特征。 电子能量中的分布将与 构象取代的分布。 2。调查光谱的变化如何用于检测变化 肽链，例如由复合形成诱导的肽（如Cyt C与CCP结合）或通过改变培养基条件。 3。检查蛋白质多肽链如何受光反应的影响 卟啉的含量，并考虑链如何影响照片的速率 互变异反应。 作为血红素口袋中发生的监视器，我们将使用高分辨率 荧光线结构，孔燃烧和的吸收技术 红外光谱镜。目的将通过系统地解决 比较不同的金属衍生物，不同的卟啉和不同的 蛋白质并通过改变实验条件。