Collaborative Research: Investigations of the Plant Photoreceptor Kinase Family of Phototropins

0090837 Bogomolni植物光感受器介导对光的广谱响应，范围从生理到生物化学和分子水平，并且存在于从种子萌发到营养生长的几乎所有阶段到开花和衰老的整个植物发育过程中。目前已知的光感受器是光敏色素、隐花色素和向光蛋白。趋光蛋白代表了一类新的和以前未表征的光感受器。这些结合两个FMN分子的双发色光感受器与任何已知类别的光感受器不同，并且通过独特的初始光化学作用并导致自磷酸化。本项目的重点是色素蛋白光致蛋白（nph1）和各种nph1样蛋白质的描述日期。这些蛋白质在异源系统中表达为发色团结合结构域和全长蛋白质。天然构建体和具有位点特异性突变的那些表达的蛋白质都是光活性形式。我们计划进行有限的生物化学和详细的生物物理特性的各种孤立的发色团结合域和全长蛋白质。生物化学研究将强调使用突变体构建体来探测初始光化学。后者将侧重于探索光激活光化学的分子机制及其在蛋白质水平上的后果的研究。这些研究将涉及时间分辨光学和振动光谱学。发色团结合结构域与从古细菌到哺乳动物的各种蛋白质中的结构域（所谓的PAS结构域）密切相关，并且应该为我们理解这些结构域的功能提供新的维度。

0090837BogomolniPlant photoreceptors mediate a broad spectrum of responses to light, ranging from the physiological through to the biochemical and molecular levels, and are present throughout plant development from seed germination through virtually all phases of vegetative growth to flowering and senescence. Currently well-known photoreceptors are phytochromes, cryptochromes, and phototropins. Phototropins represent a new and previously uncharacterized class of photoreceptors. These dual chromophoric photoreceptors, binding two molecules of FMN, are unlike any of the known classes of photoreceptors , and operate through an initial photochemistry that is unique and leads to autophosphorylation. The present project is focused on the chromoprotein phototropin (nph1) and the various nph1-like proteins described to date. These proteins are expressed in heterologous systems as the chromophore-binding domains and as the full length proteins. The expressed proteins both the native constructs and those with site-specific mutations are in the photoactive form. We plan to undertake a limited biochemical and detailed biophysical characterization of the various isolated chromophore-binding domains and of the full-length protein. The biochemical studies will emphasize the use of mutant constructs to probe the initial photochemistry. The latter will focus on studies probing the molecular mechanism by which light activates the photochemistry and its consequences at the protein level. These studies will involve time-resolved optical and vibrational spectroscopy. The chromophore-binding domains are closely related to domains (so-called PAS domains) in a diverse range of proteins from archaea through mammals, and should provide a new dimension to our understanding of the functions of these domains.