CRYO CRYSTALLOGRAPHY OF PHOTOCYCLE INTERMEDIATE OF PHOTOACTIVE YELLOW PROTEIN

来自所有生命王国的有机体利用光感受器 持续监测它们的光环境并调节它们的行为 和相应的发展。所有已知的生物感光器都是 由结合的有机分子组成的分子团队形成的 (称为发色团)和一种蛋白质成分。生色团 吸收光线，结果是经历了一种定义的光化学 反应。然后蛋白质感觉到发色团的变化。 组成成分，并转化为蛋白质结构变化，然后在 转弯激活了信号转导级联反应。而这位将军 方案是众所周知的很长一段时间，这的分子细节 这一过程还没有得到很好的理解。光活性黄蛋白是 一种小型细菌感光器，已被证明非常容易 结构和生物物理研究，因此提供 有机会研究光驱动的信号传递过程 分子细节中的生物光感受器。一部小说的组合 利用亚E X射线衍射的低温捕获策略使我们能够 确定一个非常短暂的早期中间产物的结构 细菌光传感器光活性黄的光循环 蛋白。这个结构第一次显示出，有多快 生色团异构化可以发生在受体的内部 蛋白质，并表明蛋白质是如何利用吸收的光子驱动 剩余的信号周期。所获得的洞察力不仅推动 我们对一个重要的生物功能的基本认识，但可能 也帮助我们为生物技术设计基于蛋白质的光传感器 申请。

Organisms from all kingdoms of life use photoreceptors to constantly monitor their light environment and regulate their behavior and development accordingly. All known biological photoreceptors are formed by a molecular team consisting of a bound organic molecule (called the chromophore) and a protein component. The chromophore absorbs the light and as a result undergoes a defined photochemical reaction. The change in the chromophore is then sensed by the protein component and translated into a protein structural change that then in turn activates a signal transduction cascade. While this general scheme is well known for a long time, the molecular details of this process have not been well understood. Photoactive Yellow Protein is a small bacterial photoreceptor that has proven to be very amenable to structural and biophysical studies and therefore offers the opportunity to ivestigate the light driven signaling process of a biological photoreceptor in molecular detail. Combination of a novel cryo-trapping strategy with sub E X-ray diffraction allowed us to determine the structure of a very shortlived, early intermediate in the light cycle of the bacterial light sensor Photoactive Yellow Protein. This structure shows for the first time, how rapid chromophore isomerization can occur in the interior of a receptor protein and suggests how the protein uses the absorbed photon to drive the remaining signaling cycle. The insights gained do not only drive our basic understanding of an important biological function but might also help us design protein based light sensors for biotechnological applications.