Metabolic engineering of a reduced-genome strain of Escherichia coli for L-threonine production.
Metabolic engineering of a reduced-genome strain of Escherichia coli for L-threonine production.
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DOI：
10.1186/1475-2859-8-2
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发表时间：
2009-01-07
影响因子：
6.4
通讯作者：
Kim SC
中科院分区：
文献类型：
--
作者：
Lee JH;Sung BH;Kim MS;Blattner FR;Yoon BH;Kim JH;Kim SC
删除感兴趣的代谢途径不需要的大块非必需基因可以减少不需要的副产物的产生，提高基因组稳定性，并在不影响生理学的情况下简化代谢。研究人员最近构建了一种基因组减少的大肠杆菌菌株 MDS42，其染色体缺失 14.3%。在这里，我们描述了 MDS42 基因组的重新设计，以增加必需氨基酸 L-苏氨酸的产量。为此，我们在MDS42中过度表达了反馈抗性苏氨酸操纵子（thrA * BC），删除了编码苏氨酸脱氢酶（tdh）和苏氨酸转运蛋白（tdcC和sstT）的基因，并引入了突变的苏氨酸输出蛋白（rhtA23）。与经过上述相同苏氨酸特异性修饰改造的野生型大肠杆菌菌株 MG1655 相比，通过烧瓶发酵培养细胞时，所得菌株 MDS-205 显示 L-苏氨酸产量增加约 83%。转录分析揭示了非必需基因的删除对MDS-205中枢代谢和苏氨酸途径的影响。这一结果表明，消除细胞生长不必要的基因可以提高工业菌株的生产力，很可能是通过减少代谢负担和提高细胞的代谢效率来实现的。
Deletion of large blocks of nonessential genes that are not needed for metabolic pathways of interest can reduce the production of unwanted by-products, increase genome stability, and streamline metabolism without physiological compromise. Researchers have recently constructed a reduced-genome Escherichia coli strain MDS42 that lacks 14.3% of its chromosome. Here we describe the reengineering of the MDS42 genome to increase the production of the essential amino acid L-threonine. To this end, we over-expressed a feedback-resistant threonine operon (thrA*BC), deleted the genes that encode threonine dehydrogenase (tdh) and threonine transporters (tdcC and sstT), and introduced a mutant threonine exporter (rhtA23) in MDS42. The resulting strain, MDS-205, shows an ~83% increase in L-threonine production when cells are grown by flask fermentation, compared to a wild-type E. coli strain MG1655 engineered with the same threonine-specific modifications described above. And transcriptional analysis revealed the effect of the deletion of non-essential genes on the central metabolism and threonine pathways in MDS-205. This result demonstrates that the elimination of genes unnecessary for cell growth can increase the productivity of an industrial strain, most likely by reducing the metabolic burden and improving the metabolic efficiency of cells.
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影响因子：
6.4
作者：
Gosset G
通讯作者：
Gosset G
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL
影响因子：
3.8
作者：
Andersen, DC;Swartz, J;Snedecor, B
通讯作者：
Snedecor, B
影响因子：
3.8
作者：
Bonomo, J;Gill, RT
通讯作者：
Gill, RT
影响因子：
2.7
作者：
Kim, YM;Ogawa, W;Tsuchiya, T
通讯作者：
Tsuchiya, T