PHOTOCHEMICAL PROBES OF PROTEIN FLEXIBILITY

这项拟议的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。具体目标包括勾勒出 光诱导蛋白质结合的构型(顺、反)异构化 二苯乙烯和二苯乙烯衍生物以及二吡咯甲酮的衍生物。 因为激发单重态中的旋转(导致异构化) 这些化合物的速度很快(10-100ps)，系统间交叉 相对缓慢的旋转动力学可能与荧光有关 强度和荧光寿命，以简单的方式。旋转障碍物 所提供的蛋白质环境，然后可以检测与设施。 取代基大小对异构化动力学的影响 旋转的“空间”要求，应提供更多信息 关于蛋白质结合部位的灵活性。溶剂的影响 粘度对异构化动力学的影响应与溶质蛋白有关 互动。对动态数据的解释需要知识 关于探针与蛋白质结合的部位和选择 蛋白质是至关重要的。具有“已知”结构的蛋白质将被利用。 无肌红蛋白计划用于第一批研究。各种各样的方法 包括高分辨率的核磁共振，应该能揭示结合部位。在更多方面 成熟的研究，二苯乙烯和二吡咯甲酮的衍生物，结合 酶的活性部位(例如，溶菌酶)将准备好快速探测 这些位点的结构波动及其与酶的可能关系 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.