Metabolic changes in a pyruvate kinase gene deletion mutant of Corynebacterium glutamicum ATCC 13032.
Metabolic changes in a pyruvate kinase gene deletion mutant of Corynebacterium glutamicum ATCC 13032.
复制标题
DOI：
10.1016/j.ymben.2010.01.004
复制
发表时间：
2010-07
影响因子：
8.4
通讯作者：
Kazunori Sawada;S. Zen-in;M. Wada;A. Yokota
中科院分区：
文献类型：
--
作者：
Kazunori Sawada;S. Zen-in;M. Wada;A. Yokota
为了研究丙酮酸激酶（PYK）缺陷对谷氨酸棒杆菌葡萄糖代谢的初步影响，从野生型谷氨酸棒杆菌中获得了PYK缺失突变体。glutamicum ATCC 13032的染色体克隆。然后在生物素限制诱导的谷氨酸产生条件下对突变体进行评价。该突变体表现出葡萄糖消耗的特定速率增加，生长下降，更高的谷氨酸生产，和天冬氨酸形成在谷氨酸生产阶段。突变体中磷酸烯醇式丙酮酸（PEP）羧化酶活性显著增加，PEP羧激酶活性显著降低，这表明突变体中PEP至草酰乙酸的回补途径的总体通量增强。增强的回补通量可以解释突变体中葡萄糖消耗速率的增加和谷氨酸生产率的提高。由于pyk互补菌株与野生型菌株具有相似的代谢谱，所观察到的变化代表了pyk缺失对C.谷氨酸。
To investigate primary effects of a pyruvate kinase (PYK) defect on glucose metabolism in Corynebacterium glutamicum, a pyk-deleted mutant was derived from wild-type C. glutamicum ATCC13032 using the double-crossover chromosome replacement technique. The mutant was then evaluated under glutamic acid-producing conditions induced by biotin limitation. The mutant showed an increased specific rate of glucose consumption, decreased growth, higher glutamic acid production, and aspartic acid formation during the glutamic acid production phase. A significant increase in phosphoenolpyruvate (PEP) carboxylase activity and a significant decrease in PEP carboxykinase activity occurred in the mutant, which suggested an enhanced overall flux of the anaplerotic pathway from PEP to oxaloacetic acid in the mutant. The enhanced anaplerotic flux may explain both the increased rate of glucose consumption and the higher productivity of glutamic acid in the mutant. Since the pyk-complemented strain had similar metabolic profiles to the wild-type strain, the observed changes represented intrinsic effects of pyk deletion on the physiology of C. glutamicum.