CAREER: Elucidation of the Biosynthetic and Degradative Pathways for Phycobiliproteins in Cyanobacteria

职业：阐明蓝藻藻胆蛋白的生物合成和降解途径

• 批准号: 0133441
• 负责人: Wendy Schluchter
• 金额: $ 52.31万
• 依托单位: University of New Orleans
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2009-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0133441&HistoricalAwards=false
• 关键词: CAREER; Elucidation; Biosynthetic; Degradative; Pathways

Photosynthetic organisms must balance their metabolism with the growth conditions. Cyanobacteria synthesize and degrade their light harvesting proteins, called phycobiliproteins, in response to environmental parameters such as light intensity, light quality, and nutrient availability. The phycobiliproteins absorb light in the visible region due to their bilin chromophores. The long-term goal of this research project is to understand how cyanobacteria synthesize and degrade phycobiliproteins and their bilin chromophores. The first objective is to characterize enzymes that are involved in attaching the bilins to phycobiliproteins. The role of five proteins within Synechocystis sp. PCC 6803 that are believed to be involved in bilin attachment will be characterized by mutagenesis, by in vitro enzyme assays, and by heterologous in vivo assays in Escherichia coli. A second objective is to verify the activity of a novel methyl transferase that is responsible for adding a methyl group to a conserved asparagine residue within phycobiliprotein beta-subunits has been identified. A mutant lacking this enzyme will be characterized to assess the physiological significance of this modification. A third goal involves the creation and characterization of mutant strain in which the bilin biosynthetic gene pcyA has been interrupted. Characterization of the synthesis and regulation of other tetrapyrroles within this mutant strain will be performed. This career development plan also includes training of the undergraduate and graduate students in performing the research and contains innovative efforts for encouraging junior high, high school, and undergraduate students to contemplate scientific careers. Additionally, new coursework will be created to train biology students in modern molecular and biochemical techniques. This project is funded jointly by the Molecular Biochemistry and Metabolic Biochemistry Programs.

光合生物必须在生长条件下平衡其新陈代谢。 蓝细菌合成和降解它们的捕光蛋白，称为藻胆蛋白，以响应环境参数，如光强度，光质量和营养物质的可用性。 藻胆蛋白由于其胆色素发色团而吸收可见光区域中的光。本研究计划的长期目标是了解蓝细菌如何合成和降解藻胆蛋白及其胆色素发色团。第一个目标是表征参与将胆色素附着到藻胆蛋白的酶。在集胞藻属PCC 6803中的五种蛋白质被认为参与胆色素附着的作用将通过诱变、体外酶测定和大肠杆菌中的异源体内测定来表征。 第二个目的是验证一种新的甲基转移酶的活性，该甲基转移酶负责将甲基添加到藻胆蛋白β亚基内的保守天冬酰胺残基上。将表征缺乏该酶的突变体以评估该修饰的生理学意义。第三个目标涉及突变菌株的创建和表征，其中胆色素生物合成基因pcyA已被中断。 将对该突变株中其他四吡咯的合成和调节进行表征。该职业发展计划还包括对本科生和研究生进行研究培训，并包含鼓励初中、高中和本科生考虑科学职业的创新努力。此外，将创建新的课程，以培养生物学学生在现代分子和生物化学技术。 该项目由分子生物化学和代谢生物化学计划共同资助。