TIME RESOLVED SOLUTION SCATTERING ON PHOTOACTIVE YELLOW PROTEIN

细菌感光体PYP提供了独特的机会 来研究生物传感过程的原子细节。 结构 PYP的基态和两个中间体的结构， 光周期已经通过时间分辨蛋白质 结晶学 虽然光循环动力学的相似性， 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，一直存在对 晶体学结果与溶液中过程的相关性。 最近的生物化学实验提出， 与光周期相关的结构变化 在溶液中比在晶体中观察到的大。 一项研究 表明多达40%的蛋白质是瞬时解折叠的， 在光周期中。 为了获得直接证据， 在PYP光照期间没有大规模蛋白质结构变化 在解决方案周期中，我们正在进行毫秒级的时间分辨小 激光闪光激发的角解X射线散射实验 SSRl处的PYP样品。

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.