The Function of Low Molecular-Weight Polypeptides in Photosystem II

光系统II含有至少10种多肽， 约占已知植物总数的50% 光系统II多肽，分子量低于 其中10,000人的功能大多未知。 有的已经 被示出为由小的开放阅读帧编码， 叶绿体DNA 还有其他小型开放式阅读框架 编码推测为 其他光系统III组分。 的目的 建议使用特异性诱变技术， 删除蓝藻中的互补基因 染色体 由于光系统II的相似性 植物和蓝藻的复合物，这将提供一个 快速测定小分子多肽功能的方法 在光系统II中。 然后将进行定点诱变。 用于确定特定氨基酸的作用，或 多肽的特定区域，在光系统II中 组装和功能。 将产生抗血清， 合成多肽匹配开放的产物 阅读框，用于识别工厂中的产品 光系统II核心制剂。 基因突变对 光系统II的功能和组装将研究使用 一系列技术，包括叶绿素荧光 发射光谱，氧极谱法，快速吸收 光谱法和Western和北方印迹法。

Photosystem II contains at least 10 polypeptides, approximately 50% of the total number of known plant photosystem II polypeptides, with molecular weights of under 10,000 whose function is mostly unknown. Some have been shown to be encoded by small open reading frames in chloroplast DNA. Still other small open reading frames encode putative membrane polypeptides speculated to be additional photosystem III components. The aim of the proposal is to use techniques of specific mutagenesis to delete the complementary genes from the cyanobacterial chromosome. Because of the similarity of photosystem II complexes from plants ad cyanobacteria this will provide a rapid method to assess the function of the small polypeptides in photosystem II. Site directed mutagenesis will then be used to determine the role of specific amino acids, or specific regions of the polypeptides, in photosystem II assembly and function. Antisera will be raised against synthetic polypeptides matching the products of the open reading frames and used to identify the products in plant photosystem II core preparations. The impact of mutations on photosystem II function and assembly will be studied using a range of techniques including chlorophyll fluorescence emission spectroscopy, oxygen polarography, rapid absorption spectroscopy, and western and northern blotting.