TRYPTOPHAN PHOTOPHYSICS AND PROTEIN DYNAMICS

色氨酸光物理学和蛋白质动力学

• 批准号: 2178435
• 负责人: BRUCE S HUDSON
• 金额: $ 10.36万
• 依托单位: UNIVERSITY OF OREGON
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-04-01 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2178435
• 关键词: Raman spectrometry; bacteriophage T4; biophysics; chemical models; computer simulation; dipole moment; fluorescence; lysozyme; magnetic field; molecular dynamics; mutant; nuclear magnetic resonance spectroscopy; photobiology; site directed mutagenesis; thermodynamics; time resolved data; tryptophan

The photophysics of tryptophan in proteins will be investigated with emphasis on the origin of the complex (non-exponential or multi- exponential) fluorescence decay. Mutants of bacteriophage T4 lysozyme containing single tryptophan residues and other replacements adjacent to the tryptophan residue will be constructed. Mutations that increase the fluorescence quantum yield of tryptophan 138 have been found to decrease the complexity of the fluorescence decay. It is thus hypothesized that there is a relationship between the excited state population decay kinetics and the collisional quenching process. This may involve the existence of multiple slowly interconverting conformational states ("rotamers") or be a direct consequence of a reversibility of the quenching process. This distinction is important to the interpretation of fluorescence anisotropy experiments. Experiments are proposed that are designed to distinguish between these two mechanisms and at further enlarging our understanding of the photophysics of tryptophan - and its use as a sensitive and selective probe of protein structure and dynamics. If "rotamer" subspecies exist, they will be characterized in terms of their transition dipole orientation and interconversion rates. The presence of heterogeneity in the solid state will be investigated using Raman and fluorescence methods.

将研究蛋白质中色氨酸的光物理学 强调复数的起源（非指数或多数） 指数）荧光衰减。 噬菌体T4溶菌酶突变体 含有单个色氨酸残基和邻近的其他替代物 将构建色氨酸残基。 增加的突变 色氨酸138的荧光量子产率被发现降低 荧光衰减的复杂性。 因此假设 激发态布居衰变之间存在关系 动力学和碰撞淬火过程。 这可能涉及到 存在多种缓慢相互转换的构象状态 （“旋转异构体”）或是可逆性的直接结果 淬火工艺。 这种区别对于解释很重要 荧光各向异性实验。 建议进行的实验是 旨在区分这两种机制并进一步 扩大我们对色氨酸及其光物理学的理解 用作蛋白质结构和动力学的灵敏和选择性探针。 如果存在“旋转异构体”亚种，它们的特征将是 它们的跃迁偶极子取向和相互转化率。 这 将使用以下方法研究固态中异质性的存在 拉曼和荧光方法。