TIME RESOLVED SOLUTION SCATTERING ON PHOTOACTIVE YELLOW PROTEIN

细菌光感受器PYP提供了独特的机会 以原子细节研究生物传感过程。该结构 PYP的基态和两个中间体的结构 光周期是由时间分辨蛋白质决定的 结晶学。而光循环动力学的相似性在于 晶体和溶液已经建立，晶体 中间体的结构解释了许多光谱结果 从解决方案研究中，人们一直对 溶液中过程的结晶学结果的相关性。 最近的生物化学实验提出了一种观点，即 与光周期相关的结构变化实质上是 在溶液中比在晶体中观察到的大。一项研究 表明多达40%的蛋白质是瞬间展开的 在光周期中。以获得直接证据证明存在或 PYP光期间没有大尺度的蛋白质结构变化 在解决方案中循环，我们正在执行毫秒时间解析小 激光闪光灯激活的角溶液X射线散射实验 SSRL的PYP样本。

The bacterial photoreceptor PYP has provided unique opportunities to study a biological sensing process in atomic detail. The structure of PYP in the ground state and the structure of two intermediates in the light cycle have been determined by time-resolved protein crystallography. While the similarity of the light cycle kinetics in the crystal and in solution has been established and the crystal structures of the intermediates explain many spectroscopic results from solution studies there has been a pesistent concern about the relevance of crystallographic results for processes in solution. Recent biochemical experiments have lead to the proposal that the structural changes associated with the light cycle are substantially larger in solution than those observed in the crystal. One study suggests that as much as 40% of the protein is tansiently unfolded during the light cycle. To gain direct evidence for the presence or absence of large scale protein structural changes during the PYP light cycle in solution we are carrying out millisecond time-resolve small angle solution X-ray scattering experiments of laser flash activated PYP samples at SSRl.