title: DHA Production in Escherichia coli by Expressing Reconstituted Key Genes of Polyketide Synthase Pathway from Marine Bacteria.
abstract: The gene encoding phosphopantetheinyl transferase (PPTase), pfaE, a component of the polyketide synthase (PKS) pathway, is crucial for the production of docosahexaenoic acid (DHA, 22:6ω3), along with the other pfa cluster members pfaA, pfaB, pfaC and pfaD. DHA was produced in Escherichia coli by co-expressing pfaABCD from DHA-producing Colwellia psychrerythraea 34H with one of four pfaE genes from bacteria producing arachidonic acid (ARA, 20:4ω6), eicosapentaenoic acid (EPA, 20:5ω3) or DHA, respectively. Substitution of the pfaE gene from different strain source in E. coli did not influence the function of the PKS pathway producing DHA, although they led to different DHA yields and fatty acid profiles. This result suggested that the pfaE gene could be switchable between these strains for the production of DHA. The DHA production by expressing the reconstituted PKS pathway was also investigated in different E. coli strains, at different temperatures, or with the treatment of cerulenin. The highest DHA production, 2.2 mg of DHA per gram of dry cell weight or 4.1% of total fatty acids, was obtained by co-expressing pfaE(EPA) from the EPA-producing strain Shewanella baltica with pfaABCD in DH5α. Incubation at low temperature (10-15°C) resulted in higher accumulation of DHA compared to higher temperatures. The addition of cerulenin to the medium increased the proportion of DHA and saturated fatty acids, including C12:0, C14:0 and C16:0, at the expense of monounsaturated fatty acids, including C16:1 and C18:1. Supplementation with 1 mg/L cerulenin resulted in the highest DHA yield of 2.4 mg/L upon co-expression of pfaE(DHA) from C. psychrerythraea.
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China.
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Peng
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China.
authors.forename: Wen-Chao
authors.initials: WC
authors.lastname: Chen
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China.
authors.forename: Kang
authors.initials: K
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China.
authors.forename: Lian
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China.|Hubei Key Laboratory of Lipid Chemistry and Nutrition, Wuhan, China.
authors.forename: Xia
authors.initials: X
authors.lastname: Wan
mesh_terms: D034241:Alteromonadaceae / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D053898:Biosynthetic Pathways / Q000235:genetics; D002569:Cerulenin / Q000494:pharmacology; D004281:Docosahexaenoic Acids / Q000096:biosynthesis*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D054872:Fatty Acid Synthesis Inhibitors / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D060847:Metabolic Engineering / Q000379:methods; D005810:Multigene Family; D048630:Polyketide Synthases / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012623:Seawater / Q000382:microbiology; D017386:Sequence Homology, Amino Acid; D017855:Transferases (Other Substituted Phosphate Groups) / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D054872:Fatty Acid Synthesis Inhibitors; C082662:phosphopantetheinyl transferase; D002569:Cerulenin; D004281:Docosahexaenoic Acids; D048630:Polyketide Synthases; D017855:Transferases (Other Substituted Phosphate Groups)