大肠杆菌中 l-甲硫氨酸生物合成途径模块基因扰动的局部代谢响应。
Local metabolic response of Escherichia coli to the module genetic perturbations in l-methionine biosynthetic pathway.
机构信息
Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, PR China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, PR China.
Key Laboratory of Bioorganic Synthesis of Zhejiang Province, College of Biotechnology and Bioengineering, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, PR China; The National and Local Joint Engineering Research Center for Biomanufacturing of Chiral Chemicals, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou 310014, PR China.
出版信息
J Biosci Bioeng. 2023 Mar;135(3):217-223. doi: 10.1016/j.jbiosc.2022.12.010. Epub 2023 Jan 26.
l-Methionine biosynthesis is through multilevel regulated and multibranched biosynthetic pathway (MRMBP). Because of the complex regulatory mechanism and the imbalanced metabolic flux between branched pathways, microbial production of l-methionine has not been commercialized. In this study, local metabolic response in MRMBP of l-methionine was investigated and various crucial genes in branched pathways were determined. In l-serine pathway, the crucial gene was serABC. In O-succinyl homoserine (OSH) pathway, which was the C4 backbone of l-methionine, metB and metL controlled the metabolic flux jointly. In l-cysteine pathway, the crucial gene cysE could disturb the flux distribution of local network in l-methionine biosynthesis. However, no crucial gene for l-methionine production in 5-methyl tetrahydrofolate (CH-THF) pathway was found. The relation between these pathways was also researched. l-Serine pathway, as the upstream pathway of l-cysteine and CH-THF, played a crucial role in l-methionine biosynthesis. l-Cysteine pathway showed the strongest controlling force of the metabolic flux, and OSH pathway was second to l-cysteine pathway. In contrast, CH-THF pathway was the weakest, which was probably the mainly limited steps at present and had great potential in further research. In addition, constructed W3110 IJAHFEBC/pA∗HAmL was able to produce 2.62 g/L l-methionine in flask. This study is instructive for l-methionine biosynthesis and provides a new research method of biosynthesizing other metabolic products in MRMBPs.
l-蛋氨酸的生物合成是通过多层次调控和多分支生物合成途径（MRMBP）进行的。由于复杂的调控机制和分支途径之间代谢通量的不平衡，微生物生产 l-蛋氨酸尚未实现商业化。本研究探讨了 l-蛋氨酸 MRMBP 中的局部代谢响应，并确定了分支途径中的各种关键基因。在 l-丝氨酸途径中，关键基因是 serABC。在 O-琥珀酰高丝氨酸（OSH）途径中，它是 l-蛋氨酸的 C4 骨架，metB 和 metL 共同控制代谢通量。在 l-半胱氨酸途径中，关键基因 cysE 可以干扰 l-蛋氨酸生物合成中局部网络的通量分布。然而，在 5-甲基四氢叶酸（CH-THF）途径中没有发现 l-蛋氨酸生产的关键基因。还研究了这些途径之间的关系。l-丝氨酸途径作为 l-半胱氨酸和 CH-THF 的上游途径，在 l-蛋氨酸生物合成中起着关键作用。l-半胱氨酸途径显示出最强的代谢通量控制能力，OSH 途径仅次于 l-半胱氨酸途径。相比之下，CH-THF 途径是最弱的，这可能是目前的主要限制步骤，在进一步研究中有很大的潜力。此外，构建的 W3110 IJAHFEBC/pA∗HAmL 在摇瓶中能够生产 2.62 g/L 的 l-蛋氨酸。本研究对 l-蛋氨酸的生物合成具有指导意义，并为 MRMBP 中其他代谢产物的生物合成提供了一种新的研究方法。
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