title: Programming Saposin-Mediated Compensatory Metabolic Sinks for Enhanced Ubiquinone Production.
abstract: 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 CoQ10production. 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 CoQ8over the wild type strain. Further investigation revealed that hSapB-mediated sink systems could also improve the CoQ10production 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.
authors.affiliation: School of Life Science and Technology, Xi'an Jiaotong University , Xi'an 710049, Shannxi, China.|Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an Jiaotong University , Xi'an 710049, Shannxi, China.
authors.forename: Wen
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 117585 Singapore.|Temasek Laboratories, National University of Singapore , T-Lab Building 5A, 117411 Singapore.
authors.forename: Jifeng
authors.initials: J
authors.lastname: Yuan
authors.affiliation: School of Life Science and Technology, Xi'an Jiaotong University , Xi'an 710049, Shannxi, China.|Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an Jiaotong University , Xi'an 710049, Shannxi, China.
authors.forename: Shuiyun
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore , 117585 Singapore.
authors.forename: Chi-Bun
authors.initials: CB
authors.lastname: Ching
authors.affiliation: School of Life Science and Technology, Xi'an Jiaotong University , Xi'an 710049, Shannxi, China.|Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an Jiaotong University , Xi'an 710049, Shannxi, China.
authors.forename: Jiankang
authors.initials: J
authors.lastname: Liu
mesh_terms: D001669:Biochemical Phenomena; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005285:Fermentation; D006801:Humans; D000074041:Microorganisms, Genetically-Modified; D010957:Plasmids / Q000235:genetics / Q000378:metabolism; D049231:Saposins / Q000378:metabolism*; D014451:Ubiquinone / Q000031:analogs & derivatives* / Q000096:biosynthesis; D014815:Vitamins / Q000378:metabolism*
chemical_list: D049231:Saposins; D014815:Vitamins; D014451:Ubiquinone; C024989:coenzyme Q10
keywords: metabolic sink; modular pathway rewiring; saposin; synthetic biology; ubiquinone-binding protein