title: Functional balance between enzymes in malonyl-CoA pathway for 3-hydroxypropionate biosynthesis.
abstract: 3-Hydroxypropionate (3HP) is an important platform chemical, and four 3HP biosynthetic routes were reported, in which the malonyl-CoA pathway has some expected advantages but presented the lowest 3HP yield. Here, we demonstrated that this low yield was caused by a serious functional imbalance between MCR-C and MCR-N proteins, responsible for the two-step reduction of malonyl-CoA to 3HP. Then we minimized the enzyme activity imbalance by directed evolution of rate-limiting enzyme MCR-C and fine tuning of MCR-N expression level. Combined with culture conditions optimization, our engineering approaches increased the 3HP titer 270-fold, from 0.15 g/L to 40.6 g/L, representing the highest 3HP production via malonyl-CoA pathway so far. This study not only significantly improved the 3HP productivity of recombinant Escherichia coli strain, but also proved the importance of metabolic balance in a multistep biosynthetic pathway, which should be always considered in any metabolic engineering study.
authors.affiliation: CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Changshui
authors.initials: C
authors.lastname: Liu
authors.affiliation: Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China.
authors.forename: Yamei
authors.initials: Y
authors.lastname: Ding
authors.affiliation: CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
authors.forename: Rubing
authors.initials: R
authors.lastname: Zhang
authors.affiliation: CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China.
authors.forename: Huizhou
authors.initials: H
authors.lastname: Liu
authors.affiliation: CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China. Electronic address: xianmo@qibebt.ac.cn.
authors.forename: Mo
authors.initials: M
authors.lastname: Xian
authors.affiliation: CAS Key Lab of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China. Electronic address: zhaoguang@qibebt.ac.cn.
authors.forename: Guang
authors.initials: G
authors.lastname: Zhao
mesh_terms: D019020:Directed Molecular Evolution / Q000379:methods; D004789:Enzyme Activation; D004926:Escherichia coli / Q000502:physiology*; D019344:Lactic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis / Q000302:isolation & purification; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000502:physiology*; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D019344:Lactic Acid; C031601:hydracrylic acid; D010088:Oxidoreductases; C454539:malonyl-Coa reductase
keywords: 3-hydroxypropionate; Enzymatic activity imbalance; Malonyl-CoA pathway; Malonyl-CoA reductase; Recombinant E. coli