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- Englund, Elias, et al.
(author)
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Expanding Extender Substrate Selection for Unnatural Polyketide Biosynthesis by Acyltransferase Domain Exchange within a Modular Polyketide Synthase
- 2023
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In: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 145:16, s. 8822-8832
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Journal article (peer-reviewed)abstract
- Modular polyketide synthases (PKSs) are poly-merases that employ alpha-carboxyacyl-CoAs as extender substrates. This enzyme family contains several catalytic modules, where each module is responsible for a single round of polyketide chain extension. Although PKS modules typically use malonyl-CoA or methylmalonyl-CoA for chain elongation, many other malonyl-CoA analogues are used to diversify polyketide structures in nature. Previously, we developed a method to alter an extension substrate of a given module by exchanging an acyltransferase (AT) domain while maintaining protein folding. Here, we report in vitro polyketide biosynthesis by 13 PKSs (the wild-type PKS and 12 AT-exchanged PKSs with unusual ATs) and 14 extender substrates. Our similar to 200 in vitro reactions resulted in 13 structurally different polyketides, including several polyketides that have not been reported. In some cases, AT-exchanged PKSs produced target polyketides by >100-fold compared to the wild-type PKS. These data also indicate that most unusual AT domains do not incorporate malonyl-CoA and methylmalonyl-CoA but incorporate various rare extender substrates that are equal to in size or slightly larger than natural substrates. We developed a computational workflow to predict the approximate AT substrate range based on active site volumes to support the selection of ATs. These results greatly enhance our understanding of rare AT domains and demonstrate the benefit of using the proposed PKS engineering strategy to produce novel chemicals in vitro.
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| 2. |
- Zhan, Chunjun, 1986, et al.
(author)
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Reprogramming methanol utilization pathways to convert Saccharomyces cerevisiae to a synthetic methylotroph
- 2023
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In: Nature Catalysis. - 2520-1158. ; 6:5, s. 435-450
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Journal article (peer-reviewed)abstract
- Methanol, an organic one-carbon (C1) compound, represents an attractive alternative carbon source for microbial fermentation. Despite considerable advancements in methanol utilization by prokaryotes such as Escherichia coli, engineering eukaryotic model organisms such as Saccharomyces cerevisiae into synthetic methylotrophs remains challenging. Here, an engineered module circuit strategy combined with adaptive laboratory evolution was applied to engineer S. cerevisiae to use methanol as the sole carbon source. We revealed that the evolved glyoxylate-based serine pathway plays an important role in methanol-dependent growth by promoting formaldehyde assimilation. Further, we determined that the isoprenoid biosynthetic pathway was upregulated, resulting in an increased concentration of squalene and ergosterol in our evolved strain. These changes could potentially alleviate cell membrane damage in the presence of methanol. This work sets the stage for expanding the potential of exploiting S. cerevisiae as a potential organic one-carbon platform for biochemical or biofuel production. [Figure not available: see fulltext.].
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