Carotenoid Cyclase Enzymes from Arabidopsis thaliana: Structure, Function, and Interactions

拟南芥中的类胡萝卜素环化酶：结构、功能和相互作用

• 批准号: 9631257
• 负责人: Francis Cunningham
• 金额: $ 30万
• 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: 1996
• 资助国家: 美国
• 起止时间: 1996-07-01 至 2000-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9631257&HistoricalAwards=false
• 关键词: Carotenoid; Cyclase; Enzymes; Arabidopsis; thaliana

9631257 Cunningham The cyclization of lycopene is a key branch point in the pathway carotenoid biosynthesis. Two types of cyclic end groups are commonly found in higher plant carotenoids: the ( and ( cyclase enzymes are encoded by homologous genes in Arabidopsis thaliana, and both enzymes us the linear, symmetrical lycopene as a substrate. However, the ( cyclase adds only one ring while the ( cyclase introduces a ring at both ends of the molecule. The objectives of this research are to examine and compare substrate utilization and product formation by the ( and ( cyclases of A. thaliana, to identify functional regions and amino acid residues within these two enzymes, and to ascertain whether cyclase-cyclase interactions play a role in enzyme function. Carotenoids with cyclic end groups are essential components of the photosynthetic membranes in all plants, algae and cyanobacteria. These lipid-soluble compounds protect against photooxidation, harvest light for photosynthesis, and dissipate excess light energy absorbed by the antenna pigments. The accumulation of carotenoid pigments in the photosynthetic membranes is closely coordinated with the biosynthesis and assembly of the photosynthetic apparatus. The regulatory mechanisms that serve to coordinated these processes are obscure. The classical biochemical approaches have been of limited value in the study of the membrane-associated enzymes of the carotenoid pathway, therefore the approach to be taken is largely a genetic one. The results of this research will provide valuable information on the operation and control of the essential plant pathway of carotenoid biosynthesis, and can provide insights on the functioning and regulation of other metabolic pathways that involve membrane-associated multienzyme complexes.

番茄红素的环化是类胡萝卜素生物合成途径中的一个关键分支点。在高等植物类胡萝卜素中常见的环状末端基团有两种：环化酶和环化酶在拟南芥中由同源基因编码，两种酶都以线形对称的番茄红素为底物。然而，环化酶只增加一个环，而环化酶在分子的两端引入一个环。本研究的目的是研究和比较拟南芥（拟南芥）和（拟南芥）环化酶对底物的利用和产物的形成，确定这两种酶的功能区域和氨基酸残基，并确定环化酶-环化酶相互作用是否在酶的功能中起作用。具有环端基团的类胡萝卜素是所有植物、藻类和蓝藻的光合膜的重要组成部分。这些脂溶性化合物防止光氧化，为光合作用收集光，并消散天线色素吸收的多余光能。类胡萝卜素在光合膜中的积累与光合机构的生物合成和组装密切相关。协调这些过程的监管机制是模糊的。经典的生物化学方法在类胡萝卜素途径的膜相关酶的研究中价值有限，因此要采取的方法主要是遗传方法。本研究结果将为揭示植物类胡萝卜素生物合成的基本途径的运作和调控提供有价值的信息，并为揭示其他涉及膜相关多酶复合物的代谢途径的功能和调控提供见解。