Programming Saposin-Mediated Compensatory Metabolic Sinks for Enhanced Ubiquinone Production

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• 作者：Wen Xu ; Jifeng Yuan ; Shuiyun Yang ; Chi-Bun Ching ; Jiankang Liu
• 刊名：ACS Synthetic Biology
• 出版年：2016
• 出版时间：December 16, 2016
• 年：2016
• 卷：5
• 期：12
• 页码：1404-1411
• 全文大小：446K
• ISSN：2161-5063

文摘

Microbial synthesis of ubiquinone by fermentation processes has been emerging in recent years. However, as ubiquinone is a primary metabolite that is tightly regulated by the host central metabolism, tweaking the individual pathway components could only result in a marginal improvement on the ubiquinone production. Given that ubiquinone is stored in the lipid bilayer, we hypothesized that introducing additional metabolic sink for storing ubiquinone might improve the CoQ₁₀ production. As human lipid binding/transfer protein saposin B (hSapB) was reported to extract ubiquinone from the lipid bilayer and form the water-soluble complex, hSapB was chosen to build a compensatory metabolic sink for the ubiquinone storage. As a proof-of-concept, hSapB-mediated metabolic sink systems were devised and systematically investigated in the model organism of Escherichia coli. The hSapB-mediated periplasmic sink resulted in more than 200% improvement of CoQ₈ over the wild type strain. Further investigation revealed that hSapB-mediated sink systems could also improve the CoQ₁₀ production in a CoQ₁₀-hyperproducing E. coli strain obtained by a modular pathway rewiring approach. As the design principles and the engineering strategies reported here are generalizable to other microbes, compensatory sink systems will be a method of significant interest to the synthetic biology community.