Systems metabolic engineering of Escherichia coli for L-threonine production.
Systems metabolic engineering of Escherichia coli for L-threonine production.
复制标题
大肠杆菌的系统代谢工程，用于L-苏氨酸生产。
DOI：
10.1038/msb4100196
复制
发表时间：
2007
影响因子：
9.9
通讯作者：
Lee, Sang Yup
中科院分区：
文献类型：
--
作者：
Lee, Kwang Ho;Park, Jin Hwan;Kim, Tae Yong;Kim, Hyun Uk;Lee, Sang Yup
由于很难合理设计复杂和高度调控的代谢网络，氨基酸生产者传统上是通过重复随机突变来发展的。在这里，我们报道了用系统代谢工程的方法培育基因定义的L-苏氨酸高产大肠杆菌菌株。天冬氨酸激酶I和III(分别由thrA和lysC编码)和转录衰减调节(位于thrL)的反馈抑制被消除。通过删除TdH和突变Ilva来移除苏氨酸的降解途径。删除了meta和lysa基因，使更多的前体可用于苏氨酸的生物合成。通过转录组分析结合硅通量响应分析进一步确定待工程的目的基因，并对其表达水平进行相应的调控。最终的工程菌能够生产苏氨酸受体，每克葡萄糖产量为0.393克，补料分批培养产量为82.4g/L苏氨酸。本文报道的系统代谢工程策略可广泛用于开发基因定义的生物体，以有效地生产各种生物制品。
Amino-acid producers have traditionally been developed by repeated random mutagenesis owing to the difficulty in rationally engineering the complex and highly regulated metabolic network. Here, we report the development of the genetically defined L-threonine overproducing Escherichia coli strain by systems metabolic engineering. Feedback inhibitions of aspartokinase I and III (encoded by thrA and lysC, respectively) and transcriptional attenuation regulations (located in thrL) were removed. Pathways for Thr degradation were removed by deleting tdh and mutating ilvA. The metA and lysA genes were deleted to make more precursors available for Thr biosynthesis. Further target genes to be engineered were identified by transcriptome profiling combined with in silico flux response analysis, and their expression levels were manipulated accordingly. The final engineered E. coli strain was able to produce Thr with a high yield of 0.393 g per gram of glucose, and 82.4 g/l Thr by fed-batch culture. The systems metabolic engineering strategy reported here may be broadly employed for developing genetically defined organisms for the efficient production of various bioproducts.