Trenchard IJ, Siddiqui MS, Thodey K, Smolke CD. De novo production of the key branch point benzylisoquinoline alkaloid reticuline in yeast.
Metab Eng 2015;
31:74-83. [PMID:
26166409 DOI:
10.1016/j.ymben.2015.06.010]
[Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 06/22/2015] [Accepted: 06/30/2015] [Indexed: 12/28/2022]
Abstract
Microbial biosynthesis for plant-based natural products, such as the benzylisoquinoline alkaloids (BIAs), has the potential to address limitations in plant-based supply of established drugs and make new molecules available for drug discovery. While yeast strains have been engineered to produce a variety of downstream BIAs including the opioids, these strains have relied on feeding an early BIA substrate. We describe the de novo synthesis of the major BIA branch point intermediate reticuline via norcoclaurine in Saccharomyces cerevisiae. Modifications were introduced into yeast central metabolism to increase supply of the BIA precursor tyrosine, allowing us to achieve a 60-fold increase in production of the early benzylisoquinoline scaffold from fed dopamine with no supply of exogenous tyrosine. Yeast strains further engineered to express a mammalian tyrosine hydroxylase, four mammalian tetrahydrobiopterin biosynthesis and recycling enzymes, and a bacterial DOPA decarboxylase produced norcoclaurine de novo. We further increased production of early benzylisoquinoline scaffolds by 160-fold through introducing mutant tyrosine hydroxylase enzymes, an optimized plant norcoclaurine synthase variant, and optimizing culture conditions. Finally, we incorporated five additional plant enzymes--three methyltransferases, a cytochrome P450, and its reductase partner--to achieve de novo production of the key branch point molecule reticuline with a titer of 19.2 μg/L. These strains and reconstructed pathways will serve as a platform for the biosynthesis of diverse natural and novel BIAs.
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