PHOTOCHEMICAL PROBES OF PROTEIN FLEXIBILITY

本研究的目标是开发光化学探针， 亚纳秒时间内球状蛋白质结构涨落动力学 政权 具体目标包括： 光诱导的蛋白质结合构象（顺反）异构化 二苯乙烯和二苯乙烯衍生物以及二吡咯甲烯酮衍生物。 因为激发单重态的旋转（导致异构化） 这些化合物是快速的（10-100 ps）和系统间的交叉是 相对较慢的旋转动力学可能与荧光有关 强度和荧光寿命。 旋转势垒 然后可以方便地检测到蛋白质环境提供的蛋白质。 取代基大小对异构化动力学的影响， “空格”要求旋转，应给出附加信息 蛋白质结合位点的灵活性。 溶剂的影响 粘度对异构化动力学的影响应与溶剂蛋白质有关 交互. 动态数据的解释需要知识 关于探针与蛋白质结合的位点以及 蛋白质是关键。 将使用具有“已知”结构的蛋白质。 第一项研究计划使用脱辅基肌红蛋白。 各种方法 包括高分辨率NMR应该揭示结合位点。 更 成熟的研究，芪和二吡咯甲烯酮的衍生物，结合到 酶的活性位点（例如，溶菌酶）将准备快速探测 这些位点的结构波动以及与酶的可能关系 功能

The goal of the proposed research is to develop photochemical probes of globular protein structural fluctuation dynamics in the subnanosecond time regime. Specific aims include the delineation of the dynamics of the light-induced configurational (cis trans) isomerization of protein-bound stilbene and stilbene derivatives and of dipyrromethenone derivatives. Because rotation (leading to isomerization) in the excited singlet states of these compounds is fast (10-100 ps) and intersystem crossing is relatively slow, rotational dynamics can be related to fluorescence intensities and fluorescence lifetimes in simple ways. Rotational barriers provided by the protein environment can then be detected with facility. Effects of substituent size on isomerization dynamics, reflective of the "space" requirements for rotation, should yield additional information about the flexibility of the protein binding site. Effects of solvent viscosity on isomerization dynamics should relate to solvent protein interactions. Interpretation of dynamical data will require knowledge about the sites of binding of the probes to the protein and choice of proteins is critical. Proteins with "known" structures will be utilized. Apomyoglobin is planned for the first studies. A variety of approaches including high resolution nmr should reveal the binding sites. In more mature studies, derivatives of stilbene and dipyrromethenone that bind to active sites of enzymes (e.g., lysozyme) will be prepared to probe fast structural fluctuations in those sites and possible relations with enzymic function.