Abstract
Synthetic biology enables microbial hosts to produce complex molecules from organisms that are rare or difficult to cultivate, but the structures of these molecules are limited to those formed by reactions of natural enzymes. The integration of artificial metalloenzymes (ArMs) that catalyse unnatural reactions into metabolic networks could broaden the cache of molecules produced biosynthetically. Here we report an engineered microbial cell expressing a heterologous biosynthetic pathway, containing both natural enzymes and ArMs, that produces an unnatural product with high diastereoselectivity. We engineered Escherichia coli with a heterologous terpene biosynthetic pathway and an ArM containing an iridium–porphyrin complex that was transported into the cell with a heterologous transport system. We improved the diastereoselectivity and product titre of the unnatural product by evolving the ArM and selecting the appropriate gene induction and cultivation conditions. This work shows that synthetic biology and synthetic chemistry can produce, by combining natural and artificial enzymes in whole cells, molecules that were previously inaccessible to nature.

This is a preview of subscription content, access via your institution
Relevant articles
Open Access articles citing this article.
-
Spheroplasts preparation boosts the catalytic potential of a squalene-hopene cyclase
Nature Communications Open Access 21 October 2022
Access options
Access Nature and 54 other Nature Portfolio journals
Get Nature+, our best-value online-access subscription
$29.99 / 30 days
cancel any time
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout




Data availability
All data are available in the main text or the Supplementary Information. Source Data for Figs. 2–4 are provided with the paper. Source data are provided with this paper.
References
Cravens, A., Payne, J. & Smolke, C. D. Synthetic biology strategies for microbial biosynthesis of plant natural products. Nat. Commun. 10, 2142 (2019).
Schwizer, F. et al. Artificial metalloenzymes: reaction scope and optimization strategies. Chem. Rev. 118, 142–231 (2018).
Wallace, S. & Balskus, E. P. Interfacing microbial styrene production with a biocompatible cyclopropanation reaction. Angew. Chem. Int. Ed. 54, 7106–7109 (2015).
Wu, S., Zhou, Y., Gerngross, D., Jeschek, M. & Ward, T. R. Chemo-enzymatic cascades to produce cycloalkenes from bio-based resources. Nat. Commun. 10, 5060 (2019).
Jeschek, M., Panke, S. & Ward, T. R. Artificial metalloenzymes on the verge of new-to-nature metabolism. Trends Biotechnol. 36, 60–72 (2018).
Chatterjee, A. et al. An enantioselective artificial suzukiase based on the biotin–streptavidin technology. Chem. Sci. 7, 673 (2016).
Abe, S. et al. Control of the coordination structure of organometallic palladium complexes in an apo-ferritin cage. J. Am. Chem. Soc. 130, 10512–10514 (2008).
Letondor, C. et al. Artificial transfer hydrogenases based on the biotin-(strept)avidin technology: fine tuning the selectivity by saturation mutagenesis of the host protein. J. Am. Chem. Soc. 128, 8320 (2006).
Skander, M. et al. Artificial metalloenzymes: (strept)avidin as host for enantioselective hydrogenation by achiral biotinylated rhodium–diphosphine complexes. J. Am. Chem. Soc. 126, 14411 (2004).
Lin, C. C., Lin, C. W. & Chan, A. S. C. catalytic hydrogenation of itaconic acid in a biotinylated pyrphos–rhodium(i) system in a protein cavity. Tetrahedron: Asymmetry 10, 1887 (1999).
Philippart, F. et al. A hybrid ring-opening metathesis polymerization catalyst based on an engineered variant of the beta-barrel protein Fhua. Chem. Eur. J. 19, 13865 (2013).
Lo, C., Ringenberg, M. R., Gnandt, D., Wilson, Y. & Ward, T. R. Artificial metalloenzymes for olefin metathesis based on the biotin–(strept)avidin technology. Chem. Commun. 47, 12065–12067 (2011).
Gu, Y., Natoli, S. N., Liu, Z., Clark, D. S. & Hartwig, J. F. Site-selective functionalization of (sp3)C−H bonds catalyzed by artificial metalloenzymes containing an iridium–porphyrin cofactor. Angew. Chem. Int. Ed. 58, 13954–13960 (2019).
Key, H. M. Beyond iron: iridium-containing P450 enzymes for selective cyclo-propanations of structurally diverse alkenes. ACS Cent. Sci. 3, 302–308 (2017).
Dydio, P., Key, H. M., Hayashi, H., Clark, D. S. & Hartwig, J. F. Chemoselective, enzymatic C–H bond amination catalyzed by a cytochrome P450 containing an Ir(Me)–PIX cofactor. J. Am. Chem. Soc. 139, 1750–1753 (2017).
Dydio, P. et al. An artificial metalloenzyme with the kinetics of native enzymes. Science 354, 102 (2016).
Key, H. M., Dydio, P., Clark, D. S. & Hartwig, J. F. Abiological catalysis by artificial haem proteins containing noble metals in place of iron. Nature 534, 534 (2016).
Jeschek, M. et al. Directed evolution of artificial metalloenzymes for in vivo metathesis. Nature 537, 661–665 (2016).
Zhao, J. et al. Genetic engineering of an artificial metalloenzyme for transfer hydrogenation of a self-immolative substrate in Escherichia coli’s periplasm. J. Am. Chem. Soc. 140, 13171–13175 (2018).
Grimm, A. R. et al. A whole cell E. coli display platform for artificial metalloenzymes: poly(phenylacetylene) production with a rhodium–nitrobindin metalloprotein. ACS Catal. 8, 2611–2614 (2018).
Heinisch, T. et al. E. coli surface display of streptavidin for directed evolution of an allylic deallylase. Chem. Sci. 9, 5383–5388 (2018).
Khanna, N., Esmieu, C., Mészáros, L. S., Lindblad, P. & Berggren, G. In vivo activation of an [FeFe] hydrogenase using synthetic cofactors. Energy Environ. Sci. 10, 1563–1567 (2017).
Song, W. J. & Tezcan, F. A. A designed supramolecular protein assembly with in vivo enzymatic activity. Science 346, 1525 (2014).
Chordia, S., Narasimhan, S., Lucini Paioni, A., Baldus, M. & Roelfes, G. In vivo assembly of artificial metalloenzymes and application in whole-cell biocatalysis. Angew. Chem. Int. Ed. 60, 5913–5920 (2021).
Lelyveld, V. S., Brustad, E., Arnold, F. H. & Jasanoff, A. Metal-substituted protein MRI contrast agents engineered for enhanced relaxivity and ligand sensitivity. J. Am. Chem. Soc. 133, 649–651 (2011).
Bordeaux, M., Singh, R. & Fasan, R. Intramolecular C(sp3)H amination of arylsulfonyl azides with engineered and artificial myoglobin-based catalysts. Bioorg. Med. Chem. 22, 5697–5704 (2014).
Reynolds, E. W., Schwochert, T. D., McHenry, M. W., Watters, J. W. & Brustad, E. M. Orthogonal expression of an artificial metalloenzyme for abiotic catalysis. ChemBioChem 18, 2380–2384 (2017).
Sreenilayam, G., Moore, E. J., Steck, V. & Fasan, R. Metal substitution modulates the reactivity and extends the reaction scope of myoglobin carbene transfer catalysts. Adv. Synth. Catal. 359, 2076–2089 (2017).
Talele, T. T. The ‘cyclopropyl fragment’ is a versatile player that frequently appears in preclinical/clinical drug molecules. J. Med. Chem. 59, 8712–8756 (2016).
Huang, W. & Wilks, A. Extracellular heme uptake and the challenge of bacterial cell membranes. Annu. Rev. Biochem. 86, 799–823 (2017).
Alonso-Gutierrez, J. et al. Metabolic engineering of Escherichia coli for limonene and perillyl alcohol production. Metab. Eng. 19, 33–41 (2013).
Ascue Avalos, G. A., Toogood, H. S., Tait, S., Messiha, H. L. & Scrutton, N. S. From bugs to bioplastics: total (+)-dihydrocarvide biosynthesis by engineered Escherichia coli. ChemBioChem 20, 785–792 (2019).
Henderson, D. P., Wyckoff, E. E., Rashidi, C. E., Verlei, H. & Oldham, A. L. Characterization of the Plesiomonas shigelloides genes encoding the heme iron utilization system. J. Bacteriol. 183, 2715–2723 (2001).
Smith, B. J. Z., Gutierrez, P., Guerrero, E., Brewer, C. J. & Henderson, D. P. Development of a method to produce hemoglobin in a bioreactor culture of Escherichia coli BL21(DE3) transformed with a plasmid containing Plesiomonas shigelloides heme transport genes and modified human hemoglobin genes. Appl. Environ. Microbiol. 77, 6703 (2011).
Wilson, Y. M., Dürrenberger, M., Nogueira, E. S. & Ward, T. R. Neutralizing the detrimental effect of glutathione on precious metal catalysts. J. Am. Chem. Soc. 136, 8928–8932 (2014).
Carter, O. A., Peters, R. J. & Croteau, R. Monoterpene biosynthesis pathway construction in Escherichia coli. Phytochemistry 64, 425–433 (2003).
Waldman, A. J. & Balskus, E. P. Discovery of a diazo-forming enzyme in cremeomycin biosynthesis. J. Org. Chem. 83, 7539–7546 (2018).
Acknowledgements
We thank D.P. Henderson for kindly sharing pHug21 plasmid. This work was supported by the Department of Energy (DOE), Laboratory Directed Research and Development funding, Joint BioEnergy Institute (https://www.jbei.org), which is supported by the DOE, Office of Science, Office of Biological and Environmental Research under contract DE-AC02-05CH11231 and National Science Foundation grant 2027943. Z.L. is an A*Star predoctoral fellow. We thank the College of Chemistry’s NMR facility for resources. Instruments in CoC-NMR are supported in part by the NIH (S10OD024998). Inductively coupled plasma mass spectrometry measurements were performed in the OHSU Elemental Analysis Core with partial support from NIH (S10RR025512).
Author information
Authors and Affiliations
Contributions
J.F.H., D.S.C., A.M. and J.D.K. conceived the project and all authors participated in designing the experiments. J.H., Z.L. and B.L.B. conducted all the experiments and collected data for the project. All authors interpreted the data and wrote the manuscript.
Corresponding authors
Ethics declarations
Competing interests
J.D.K. has a financial interest in Amyris, Lygos, Demetrix, Maple Bio, Napigen, Apertor Pharma, Ansa Biotechnologies, Berkeley Yeast and Zero Acre Farms. A provisional patent application (US application number 17/200,715; inventors: J.H., Z.L., D.S.C., J.D.K., A.M. and J.F.H.) has been filed through the Lawrence Berkeley National Laboratory based on the results presented here.
Additional information
Peer review information Nature Chemistry thanks the anonymous reviewers for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Supplementary Information
Supplementary Figs. 1–19 and Tables 1–4.
Source data
Source Data Fig. 2
Statistical Source Data
Source Data Fig. 3
Statistical Source Data
Source Data Fig. 4
Statistical Source Data
Rights and permissions
About this article
Cite this article
Huang, J., Liu, Z., Bloomer, B.J. et al. Unnatural biosynthesis by an engineered microorganism with heterologously expressed natural enzymes and an artificial metalloenzyme. Nat. Chem. 13, 1186–1191 (2021). https://doi.org/10.1038/s41557-021-00801-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/s41557-021-00801-3
This article is cited by
-
Direct visible-light-excited flavoproteins for redox-neutral asymmetric radical hydroarylation
Nature Catalysis (2023)
-
Complete integration of carbene-transfer chemistry into biosynthesis
Nature (2023)
-
Carbene chemistry for unnatural biosynthesis
Science China Life Sciences (2023)
-
Spheroplasts preparation boosts the catalytic potential of a squalene-hopene cyclase
Nature Communications (2022)
-
Mutant enzymes give ordinary bacteria unnatural powers
Nature (2021)