Carotenogenic Enzyme Complexes and Metabolic Channeling in Synechocystis PCC6803

集胞藻 PCC6803 中的胡萝卜素酶复合物和代谢通道

• 批准号: 0316448
• 负责人: Francis Cunningham
• 金额: --
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0316448&HistoricalAwards=false
• 关键词: Carotenogenic; Enzyme; Complexes; Metabolic; Channeling

Carotenoids are essential constituents of the photosynthetic apparatus in plants and cyanobacteria. These lipid-soluble yellow, orange and red pigments dissipate excess light energy and protect against potentially lethal photo-oxidation sensitized by excited state molecules of chlorophyll. The pathways leading to carotenoids and chlorophylls are inextricably linked: wherever there is chlorophyll, there must also be carotenoids. The mechanisms by which plants and cyanobacteria determine the amounts and specify the identities of the various carotenoids that accumulate in their photosynthetic membranes are being investigated in this project. Metabolic "channeling" in putative enzyme complexes of the carotenoid pathway will be examined in Synechocystis PCC6803, a cyanobacterium for which the entire genome sequence has been determined. Several Synechocystis carotenoid pathway enzymes have been "epitope tagged" at their C terminal ends in order to facilitate their isolation and purification. Polypeptides that comprise the purified carotenoid enzyme complexes will be identified by mass spectrometry. Subcellular localization of the tagged enzymes is being ascertained using an antiserum that recognizes the epitope tag. A genetic approach will be employed to identify other polypeptides that interact with carotenoid pathway enzymes. Changes in gene expression that result from an insufficiency of carotenoids will be examined to define the regulatory circuits involved in carotenogenesis. The long term goal of the investigators is to achieve a comprehensive understanding of the architecture and function of carotenoid enzyme complexes and the regulation of this pathway in Synechocystis PCC6803, a model organism for carotenoid biosynthesis and photosynthesis in higher plants and algae.An improved understanding of the mechanisms by which plants and cyanobacteria regulate the carotenoid pathway is expected to facilitate metabolic engineering of the carotenoid pathway to improve the nutritional value of plant foods. In addition to their essential functions in photosynthesis, carotenoid pigments impart an attractive yellow, orange or red colors to fruits and flowers, provide the raw material for the production of alluring fruit aromas and floral fragrances, and serve as the major source of vitamin A in the human diet. A diverse combination of graduate and undergraduate students, including minorities will participate and receive advanced training in the course of this project.

类胡萝卜素是植物和蓝细菌光合机构的重要组成部分。这些脂溶性黄色、橙子和红色色素耗散过量的光能，并防止由叶绿素的激发态分子敏化的潜在致命的光氧化。产生类胡萝卜素和叶绿素的途径是密不可分的：哪里有叶绿素，哪里就一定有类胡萝卜素。本项目正在研究植物和蓝细菌确定其光合膜中积累的各种类胡萝卜素的数量和特性的机制。代谢“通道”在假定的酶复合物的类胡萝卜素途径将在集胞藻PCC 6803，蓝藻的整个基因组序列已被确定。几种集胞藻类胡萝卜素途径酶已在其C末端被“表位标记”，以便于其分离和纯化。包含纯化的类胡萝卜素酶复合物的多肽将通过质谱法鉴定。使用识别表位标签的抗血清确定标记酶的亚细胞定位。将采用遗传方法来鉴定与类胡萝卜素途径酶相互作用的其他多肽。类胡萝卜素缺乏引起的基因表达变化将被研究，以确定参与胡萝卜素生成的调控回路。研究人员的长期目标是全面了解集胞藻PCC 6803中类胡萝卜素酶复合物的结构和功能以及该途径的调控，类胡萝卜素是高等植物和藻类类胡萝卜素生物合成和光合作用的模式生物。类胡萝卜素途径，以提高植物性食品的营养价值。除了在光合作用中的基本功能外，类胡萝卜素色素还赋予水果和花卉诱人的黄色、橙子或红色，为生产诱人的水果香味和花香提供原料，并作为人类饮食中维生素A的主要来源。研究生和本科生的多样化组合，包括少数民族将参加并在这个项目的过程中接受高级培训。