辅酶Q是一类存在于几乎所有生物体内的萜苯醌类化合物，是呼吸链的电子传递体，也是人体必需的营养物质，又称为维生素Q，然而其生物合成途径还没有完全解析。在辅酶Q合成过程中苯环需经过三次羟化修饰，其中1位羟化酶在所有真核生物中是未知的，植物的6位羟化酶也是未知的。在前期工作中，申请者通过与拟南芥辅酶Q途径已知基因共表达分析，筛选到一些候选的羟化酶基因。本项目拟通过回补大肠杆菌1位或6位羟化酶基因突变株的方法检测这些候选基因的活性，通过体外酶活测定验证它们的功能。通过分析拟南芥T-DNA突变体，过表达转基因植株及蛋白亚细胞定位来研究它们在植物体内的功能。本项目的实施，将为植物辅酶Q合成途径解析提供重要环节。

Coenzyme Q (CoQ), also known as vitamin Q, is an isoprenoid quinone produced in almost all living organisms and functions as electron transporters in respiratory chain. Despite the paramount importance of CoQ to health, its biosynthetic pathway has not been fully defined. The modification of CoQ aromatic ring involves three hydroxylations, and the enzyme responsible for the C-1 hydroxylation has not been identified in eukaryotes. Moreover, the enzyme responsible for the C-6 hydroxylation in plants remains unknown. We have isolated several candidate hydroxylases from Arabidopsis thaliana by co-expression network analysis. We plan to identify the enzyme by complementing the C-1 or C-6 hydroxylation defects in E. coli, analysis of the T-DNA insertion mutants and overexpression plants, subcellular localization and biochemical assay to verify the function of the candidate(s). The results will provide new and deep insight into the CoQ biosynthesis.