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A genetically encoded photosensitizer protein facilitates the rational design of a miniature photocatalytic CO2-reducing enzyme

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Abstract

Photosensitizers, which harness light energy to upgrade weak reductants to strong reductants, are pivotal components of the natural and artificial photosynthesis machineries. However, it has proved difficult to enhance and expand their functions through genetic engineering. Here we report a genetically encoded, 27 kDa photosensitizer protein (PSP), which facilitates the rational design of miniature photocatalytic CO2-reducing enzymes. Visible light drives PSP efficiently into a long-lived triplet excited state (PSP*), which reacts rapidly with reduced nicotinamide adenine dinucleotide to generate a super-reducing radical (PSP), which is strong enough to reduce many CO2-reducing catalysts. We determined the three-dimensional structure of PSP at 1.8 Å resolution by X-ray crystallography. Genetic engineering enabled the site-specific attachment of a nickel–terpyridine complex and the modular optimization of the photochemical properties of PSP, the chromophore/catalytic centre distance and the catalytic centre microenvironment, which culminated in a miniature photocatalytic CO2-reducing enzyme that has a CO2/CO conversion quantum efficiency of 2.6%.

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Fig. 1: Rational design of PSP and PSP2T.
Fig. 2: Crystallography characterization of PSP.
Fig. 3: Design and characterization of PSP2T.
Fig. 4: Transient absorption spectra and the spectral temporal evolution of PSP2.

Data availability

Synthetic and experimental procedures, spectroscopic and mass spectrometric data, expression, purification and crystallization for X-ray diffraction as well as additional experiments are provided in the Supplementary Information. All other data are available from the authors upon request. Protein structures have been deposited to the Protein Data Bank under accession numbers 5YR2 and 5YR3.

References

  1. 1.

    Liu, J. et al. Metalloproteins containing cytochrome, iron–sulfur or copper redox centers. Chem. Rev. 114, 4366–4469 (2014).

    CAS  Article  Google Scholar 

  2. 2.

    Marshall, N. M. et al. Rationally tuning the reduction potential of a single cupredoxin beyond the natural range. Nature 462, 113–116 (2009).

    CAS  Article  Google Scholar 

  3. 3.

    Blankenship, R. E. et al. Comparing photosynthetic and photovoltaic efficiencies and recognizing the potential for improvement. Science 332, 805–809 (2011).

    CAS  Article  Google Scholar 

  4. 4.

    Romero, E., Novoderezhkin, V. I. & van Grondelle, R. Quantum design of photosynthesis for bio-inspired solar-energy conversion. Nature 543, 355–365 (2017).

    CAS  Article  Google Scholar 

  5. 5.

    Appel, A. M. et al. Frontiers, opportunities, and challenges in biochemical and chemical catalysis of CO2 fixation. Chem. Rev. 113, 6621–6658 (2013).

    CAS  Article  Google Scholar 

  6. 6.

    Sakimoto, K. K., Wong, A. B. & Yang, P. D. Self-photosensitization of nonphotosynthetic bacteria for solar-to-chemical production. Science 351, 74–77 (2016).

    CAS  Article  Google Scholar 

  7. 7.

    Liu, C., Colon, B. C., Ziesack, M., Silver, P. A. & Nocera, D. G. Water splitting-biosynthetic system with CO2 reduction efficiencies exceeding photosynthesis. Science 352, 1210–1213 (2016).

    CAS  Article  Google Scholar 

  8. 8.

    Schuchmann, K. & Muller, V. Direct and reversible hydrogenation of CO2 to formate by a bacterial carbon dioxide reductase. Science 342, 1382–1385 (2013).

    CAS  Article  Google Scholar 

  9. 9.

    Ort, D. R. et al. Redesigning photosynthesis to sustainably meet global food and bioenergy demand. Proc. Natl Acad. Sci. USA 112, 8529–8536 (2015).

    CAS  Article  Google Scholar 

  10. 10.

    Lewis, N. S. & Nocera, D. G. Powering the planet: chemical challenges in solar energy utilization. Proc. Natl Acad. Sci. USA 103, 15729–15735 (2006).

    CAS  Article  Google Scholar 

  11. 11.

    Gray, H. B. Powering the planet with solar fuel. Nat. Chem. 1, 7–12 (2009).

    CAS  Article  Google Scholar 

  12. 12.

    Rao, H., Schmidt, L. C. S., Bonin, J. & Robert, M. Visible-light-driven methane formation from CO2 with a molecular iron catalyst. Nature 548, 74–77 (2017).

    CAS  Article  Google Scholar 

  13. 13.

    Giepmans, B. N. G., Adams, S. R., Ellisman, M. H. & Tsien, R. Y. The fluorescent toolbox for assessing protein location and function. Science 312, 217–224 (2006).

    CAS  Article  Google Scholar 

  14. 14.

    Chattoraj, M., King, B. A., Bublitz, G. U. & Boxer, S. G. Ultra-fast excited state dynamics in green fluorescent protein: multiple states and proton transfer. Proc. Natl Acad. Sci. USA 93, 8362–8367 (1996).

    CAS  Article  Google Scholar 

  15. 15.

    Pearson, A. D. et al. Trapping a transition state in a computationally designed protein bottle. Science 347, 863–867 (2015).

    CAS  Article  Google Scholar 

  16. 16.

    Wang, L., Xie, J. & Schultz, P. G. Expanding the genetic code. Annu. Rev. Biophys. Biomol. 35, 225–249 (2006).

    Article  Google Scholar 

  17. 17.

    Breslow, R. et al. Remote oxidation of steroids by photolysis of attached benzophenone groups. J. Am. Chem. Soc. 95, 3251–3262 (1973).

    CAS  Article  Google Scholar 

  18. 18.

    Breslow, R., Kitabatake, S. & Rothbard, J. Photoreactions of charged benzophenone with amphiphiles in micelles and multicomponent aggregates as conformational probes. J. Am. Chem. Soc. 100, 8156–8160 (1978).

    CAS  Article  Google Scholar 

  19. 19.

    Braun, A. M. et al. Photochemical processes of benzophenone in microheterogeneous systems. J. Am. Chem. Soc. 103, 7312–7316 (1981).

    CAS  Article  Google Scholar 

  20. 20.

    Turro, N. J., Aikawa, M. & Gould, I. R. The laser vs the lamp—a novel laser-induced adiabatic reaction and luminescence of benzophenone. J. Am. Chem. Soc. 104, 856–858 (1982).

    CAS  Article  Google Scholar 

  21. 21.

    Kauer, J. C., Erickson-Viitanen, S., Wolfe, H. R.Jr. & DeGrado, W. F. p-Benzoyl-l-phenylalanine, a new photoreactive amino acid. Photolabeling of calmodulin with a synthetic calmodulin-binding peptide. J. Biol. Chem. 261, 10695–10700 (1986).

    CAS  PubMed  Google Scholar 

  22. 22.

    Connelly, N. G. & Geiger, W. E. Chemical redox agents for organometallic chemistry. Chem. Rev. 96, 877–910 (1996).

    CAS  Article  Google Scholar 

  23. 23.

    Hammes-Schiffer, S. & Stuchebrukhov, A. A. Theory of coupled electron and proton transfer reactions. Chem. Rev. 110, 6939–6960 (2010).

    CAS  Article  Google Scholar 

  24. 24.

    Li, H. & Zhang, M. T. Tuning excited-state reactivity by proton-coupled electron transfer. Angew. Chem. Int. Ed. 55, 13132–13136 (2016).

    CAS  Article  Google Scholar 

  25. 25.

    Rebelein, J. G., Stiebritz, M. T., Lee, C. C. & Hu, Y. Activation and reduction of carbon dioxide by nitrogenase iron proteins. Nat. Chem. Biol. 13, 147–149 (2017).

    CAS  Article  Google Scholar 

  26. 26.

    Dorman, G. & Prestwich, G. D. Benzophenone photophores in biochemistry. Biochemistry 33, 5661–5673 (1994).

    CAS  Article  Google Scholar 

  27. 27.

    Kuehnel, M. F., Orchard, K. L., Dalle, K. E. & Reisner, E. Selective photocatalytic CO2 reduction in water through anchoring of a molecular Ni catalyst on CdS nanocrystals. J. Am. Chem. Soc. 139, 7217–7223 (2017).

    CAS  Article  Google Scholar 

  28. 28.

    Prier, C. K., Rankic, D. A. & MacMillan, D. W. C. Visible light photoredox catalysis with transition metal complexes: applications in organic synthesis. Chem. Rev. 113, 5322–5363 (2013).

    CAS  Article  Google Scholar 

  29. 29.

    Shih, C. et al. Tryptophan-accelerated electron flow through proteins. Science 320, 1760–1762 (2008).

    CAS  Article  Google Scholar 

  30. 30.

    Song, W. J. & Tezcan, F. A. A designed supramolecular protein assembly with in vivo enzymatic activity. Science 346, 1525–1528 (2014).

    CAS  Article  Google Scholar 

  31. 31.

    Hsia, Y. et al. Design of a hyperstable 60-subunit protein icosahedron. Nature 540, 136–139 (2016).

    Article  Google Scholar 

  32. 32.

    Kan, S. B. J., Lewis, R. D., Chen, K. & Arnold, F. H. Directed evolution of cytochrome C for carbon–silicon bond formation: bringing silicon to life. Science 354, 1048–1051 (2016).

    CAS  Article  Google Scholar 

  33. 33.

    Blomberg, R. et al. Precision is essential for efficient catalysis in an evolved Kemp eliminase. Nature 503, 418–421 (2013).

    CAS  Article  Google Scholar 

  34. 34.

    Jeschek, M. et al. Directed evolution of artificial metalloenzymes for in vivo metathesis. Nature 537, 661–665 (2016).

    CAS  Article  Google Scholar 

  35. 35.

    Dydio, P. et al. An artificial metalloenzyme with the kinetics of native enzymes. Science 354, 102–106 (2016).

    CAS  Article  Google Scholar 

  36. 36.

    Joh, N. H. et al. De novo design of a transmembrane Zn2+-transporting four-helix bundle. Science 346, 1520–1524 (2014).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

We are grateful for the financial support from the National Key Research and Development Program of China under awards 2017YFA0503704, 2016YFA0501502 and 2015CB856203; the National Science Foundation of China under awards 21750003, 91527302, U1632133, 31628004, 21473237, 31628004 and U1732264; Key Research Program of Frontier Sciences, CAS, grant numbers QYZDB-SSW-SMC032 and QYZDJ-SSW-SMC018; Tianjin Science and Technology grant 15PTCYSY00020; and Sanming Project of Medicine in Shenzhen (number SZSM201811092). We thank S. S. Zang for help with NMR spectra determination; Z. Xie for protein mass spectrometry; C. X. Zhang for ESR experiments; L. Xia for CV experiments; C. Wang and D. S. Liu for TEM experiments; J. H. Li for CD experiments and J. L. Jie for help with transient absorption spectroscopy experiments.

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Contributions

J.Y.W. conceived the study and designed the experiments. X.H.L. performed most of the experiments, and together with J.Y.W. wrote the manuscript. F.Y.K., L.W. and D.D.Z. performed protein purification, crystallization and X-ray diffraction. C.H. and Z.X. synthesized small molecules and performed enzyme activity assays. Y.L., W.M.G. and Y.H.M. inspired the work and helped to revise the manuscript.

Corresponding author

Correspondence to Jiangyun Wang.

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Liu, X., Kang, F., Hu, C. et al. A genetically encoded photosensitizer protein facilitates the rational design of a miniature photocatalytic CO2-reducing enzyme. Nature Chem 10, 1201–1206 (2018). https://doi.org/10.1038/s41557-018-0150-4

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