A highly selective biosynthetic pathway to non-natural C[subscript 50] carotenoids assembled from moderately selective enzymes
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...
| Main Authors: | , , , , , , , , |
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| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
Nature Publishing Group
2015
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| Online Access: | http://hdl.handle.net/1721.1/98477 https://orcid.org/0000-0001-5215-523X |
| Summary: | 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. |
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