Heterologous biosynthesis of triterpenoid ambrein in engineered Escherichia coli
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To genetically engineer Escherichia coli for the heterologous biosynthesis of triterpenoid, ambrein, the main bioactive component of ambergris, by constituting a novel squalene-derived ambrein biosynthetic pathway in E. coli.
The ScERG9 gene encoding the squalene synthase (SS) was integrated into the E. coli genome to generate a squalene-producing strain that supplied the central precursor squalene for the formation of cyclic triterpenoids. The mutated squalene–hopene synthase (D377C SHC) and the tetraprenyl-β-curcumene cyclase (BmeTC) were co-expressed with SS to construct a novel ambrein biosynthetic pathway in E. coli. Ambrein was produced at 2.6 mg l−1.
An E. coli chassis for ambrein production was constructed by combining the squalene synthesis module with the downstream cyclization module.
KeywordsAmbergris Ambrein Escherichia coli Heterologous biosynthesis Squalene Triterpenoid
The present work was funded by the National Basic Research Program of China (“973” Program: 2012CB721105) and the Major Research Plan of Tianjin (16YFXTSF00460).
Supplementary method—effective prediction of relative response factor RRF for epifriedelanol/ambrein in GC-FID analysis via a carbon number-based approach.
Supplementary Table 1—strains and plasmids used.
Supplementary Table 2—DNA sequences of exogenous genes used for the construction of the ambrein biosynthetic pathway in Escherichia coli.
Supplementary Table 3—oligonucleotide primers used in this study.
Supplementary Fig. 1—identification of the authentic ambergris containing ambrein via GC–MS.
Supplementary Fig. 2—quantitative analysis of ambrein production via GC-FID.
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