A highly selective biosynthetic pathway to non-natural C[subscript 50] carotenoids assembled from moderately selective enzymes

• Main Authors: Furubayashi, Maiko (Contributor), Ikezumi, Mayu (Author), Takaichi, Shinichi (Author), Maoka, Takashi (Author), Hemmi, Hisashi (Author), Ogawa, Takuya (Author), Saito, Kyoichi (Author), Tobias, Alexander V (Author), Umeno, Daisuke (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Biological Engineering (Contributor)
• Format: Article
• Language: English
• Published: Nature Publishing Group, 2015-09-14T13:47:54Z.
• Subjects: Article
• Online Access: Get fulltext

 Synthetic biology aspires to construct natural and non-natural pathways to useful compounds. However, pathways that rely on multiple promiscuous enzymes may branch, which might preclude selective production of the target compound. Here, we describe the assembly of a six-enzyme pathway in Escherichia coli for the synthesis of C[subscript 50]-astaxanthin, a non-natural purple carotenoid. We show that by judicious matching of engineered size-selectivity variants of the first two enzymes in the pathway, farnesyl diphosphate synthase (FDS) and carotenoid synthase (CrtM), branching and the production of non-target compounds can be suppressed, enriching the proportion of C[subscript 50] backbones produced. We then further extend the C[subscript 50] pathway using evolved or wild-type downstream enzymes. Despite not containing any substrate- or product-specific enzymes, the resulting pathway detectably produces only C[subscript 50] carotenoids, including ~90% C[subscript 50]-astaxanthin. Using this approach, highly selective pathways can be engineered without developing absolutely specific enzymes.