恶臭假单胞菌中一条新的戊二酸代谢途径

已报道的生物体内戊二酸代谢均通过戊二酸脱氢途径，申请人基于比较基因组学分析与前期实验结果，推测Pseudomonas putida KT2440中存在一条新的戊二酸羟基化途径。该途径涉及戊二酸羟基化酶（GHS）、L-2-羟基戊二酸氧化酶（LGO）与GntR家族转录调控蛋白（GhsR），其中GHS催化戊二酸羟基化生成L-2-羟基戊二酸；LGO催化L-2-羟基戊二酸生成2-酮基戊二酸；GhsR调控GHS、LGO的表达。本项目拟以P. putida KT2440中该戊二酸代谢新途径为研究对象，基于对各关键酶的生理功能及生化特性分析，确定GHS、LGO在戊二酸代谢中的作用；阐明GhsR调控GHS、LGO表达的具体机制；解析P. putida KT2440中L-2-羟基戊二酸的来源、积累及其抑制戊二酸代谢的机理，为揭示生物体戊二酸代谢及相关致病过程奠定理论基础。

In previous reports, glutaric acid was metabolized by glutaric acid dehydrogenation pathway. Based on the comparative genomic analysis and preliminary experimental results, we speculated that a new glutaric acid hydroxylation pathway exists in Pseudomonas putida KT2440. The new glutaric acid hydroxylation pathway involves three proteins; glutaric acid hydroxylase (GHS), L-2-hydroxyglutaric acid oxidase (LGO), and a regulatory protein of GntR family (GhsR). GHS catalyzes the hydroxylation of glutaric acid to produce L-2-hydroxyglutaric acid. LGO catalyzes the oxidation of L-2-hydroxyglutaric acid to produce 2- ketoglutarate. GhsR regulated the expression of LGO and GHS. In this project, the new glutaric acid hydroxylation pathway would be studied in depth. Based on the physiological and biochemical characteristics of each key enzyme in the new pathway, roles of LGO and GHS in glutaric acid metabolism and the regulating mechanism of GhsR would be clarified. This project could reveal the source of L-2-hydroxyglutaric acid, the reason for L-2-hydroxyglutaric acid accumulation, and the inhibition mechanism of L-2-hydroxyglutaric acid on glutaric acid metabolism in P. putida KT2440. The theoretical basis for revealing the organism glutaric acid metabolism and the related pathogenic processes would also be acquired through the accomplishment of the project.