Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Photocurrent of a single photosynthetic protein

Abstract

Photosynthesis is used by plants, algae and bacteria to convert solar energy into stable chemical energy. The initial stages of this process—where light is absorbed and energy and electrons are transferred—are mediated by reaction centres composed of chlorophyll and carotenoid complexes1. It has been previously shown that single small molecules can be used as functional components in electric2,3,4,5,6 and optoelectronic circuits7,8,9,10, but it has proved difficult to control and probe individual molecules for photovoltaic11,12,13 and photoelectrochemical applications14,15,16. Here, we show that the photocurrent generated by a single photosynthetic protein—photosystem I—can be measured using a scanning near-field optical microscope set-up. One side of the protein is anchored to a gold surface that acts as an electrode, and the other is contacted by a gold-covered glass tip. The tip functions as both counter electrode and light source. A photocurrent of 10 pA is recorded from the covalently bound single-protein junctions, which is in agreement with the internal electron transfer times of photosystem I.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Measuring the photocurrent of a single PS I.
Figure 2: The reaction-centre electron transfer chain, showing electron transfer and recombination times.
Figure 3: Current versus gap distance profiles.
Figure 4: Photocurrent analysis and histograms.

Similar content being viewed by others

References

  1. Brettel, K. Electron transfer and arrangement of the redox cofactors in photosystem I. Biochim. Biophys. Acta 1318, 322–373 (1997).

    Article  CAS  Google Scholar 

  2. Metzger, R. M. Unimolecular electronics. J. Mater. Chem. 18, 4364–4396 (2008).

    Article  CAS  Google Scholar 

  3. Reichert, J. et al. Driving current through single organic molecules. Phys. Rev. Lett. 88, 176804 (2002).

    Article  CAS  Google Scholar 

  4. Salomon, A. et al. Comparison of electronic transport measurements on organic molecules. Adv. Mater. 15, 1881–1890 (2003).

    Article  CAS  Google Scholar 

  5. Guo, X. et al. Covalently bridging gaps in single-walled carbon nanotubes with conducting molecules. Science 311, 356–359 (2006).

    Article  CAS  Google Scholar 

  6. Akkermann, H. B. & de Boer, B. Electrical conduction through single molecules and self-assembled monolayers. J. Phys. Condens. Matter 20, 13001 (2008).

    Article  Google Scholar 

  7. Dulić, D. et al. One-way optoelectronic switching of photochromic molecules on gold. Phys. Rev. Lett. 91, 207402 (2003).

    Article  Google Scholar 

  8. Battacharyya, S. et al. Optical modulation of molecular conductance. Nano Lett. 11, 2709–2714 (2011).

    Article  CAS  Google Scholar 

  9. Wu, S. W., Ogawa, N. & Ho, W. Atomic-scale coupling of photons to single-molecule junctions. Science 312, 1362–1365 (2006).

    Article  CAS  Google Scholar 

  10. Van der Molen, S. J. et al. Light-controlled conductance switching of ordered metal–molecule–metal devices. Nano Lett. 9, 76–80 (2009).

    Article  CAS  Google Scholar 

  11. Lee, I., Lee, J. W. & Greenbaum, E. Biomolecular electronics: vectorial arrays of photosynthetic reaction centers. Phys. Rev. Lett. 79, 3294–3297 (1997).

    Article  CAS  Google Scholar 

  12. Das, R. et al. Integration of photosynthetic protein molecular complexes in solid-state electronic devices. Nano Lett. 4, 1079–1083 (2004).

    Article  CAS  Google Scholar 

  13. Frolov, L., Rosenwaks, Y., Carmeli, C. & Carmeli, I. Fabrication of a photoelectronic device by direct chemical binding of the photosynthetic reaction center protein to metal surfaces. Adv. Mater. 17, 2434–2437 (2005).

    Article  CAS  Google Scholar 

  14. Grätzel, M. Photoelectrochemical cells. Nature 414, 338–344 (2001).

    Article  Google Scholar 

  15. Ham, M. H. et al. Photoelectrochemical complexes for solar energy conversion that chemically and autonomously regenerate. Nature Chem. 2, 929–936 (2010).

    Article  CAS  Google Scholar 

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

    Article  CAS  Google Scholar 

  17. Carmeli, I. et al. A photosynthetic reaction center covalently bound to carbon nanotubes. Adv. Mater. 19, 3901–3905 (2007).

    Article  CAS  Google Scholar 

  18. Kaniber, S. M., Brandstetter, M., Simmel, F. C., Carmeli, I. & Holleitner, A. W. On-chip functionalization of carbon nanotubes with Photosystem I. J. Am. Chem. Soc. 132, 2872–2873 (2010).

    Article  CAS  Google Scholar 

  19. Carmeli, I. et al. Broad band enhancement of light absorption in Photosystem I by metal nanoparticle antennas. Nano Lett. 10, 2069–2074 (2010).

    Article  CAS  Google Scholar 

  20. Stamouli, A., Frenken, J. W. M., Oosterkamp, T. H., Cogdell, R. J. & Aartsma, T. J. The electron conduction of photosynthetic protein complexes embedded in a membrane. FEBS Lett. 560, 109–114 (2004).

    Article  CAS  Google Scholar 

  21. Zhao, J. W., Davis, J. J., Sansom, M. S. P. & Hung, A. Exploring the electronic and mechanical properties of protein using conducting atomic force microscopy. J. Am. Chem. Soc. 126, 5601–5609 (2004).

    Article  CAS  Google Scholar 

  22. Lukins, P. B. & Oates, T. Single-molecule high-resolution structure and electron conduction of Photosystem II from scanning tunneling microscopy and spectroscopy. Biochim. Biophys. Acta 1409, 1–11 (1998).

    Article  CAS  Google Scholar 

  23. Reiss, B. D., Hanson, D. K. & Firestone, M. A. Evaluation of the photosynthetic reaction center protein for potential use as a bioelectronic circuit element. Biotechnol. Progr. 23, 985–989 (2007).

    Article  CAS  Google Scholar 

  24. Tsutsui, M., Taniguchi, M. & Kawai, T. Single-molecule identification via electric current noise. Nature Commun. 1, 138 (2010).

    Article  Google Scholar 

  25. Ron, I., Friedman, N., Sheves, M. & Cahen, D. Enhanced electronic conductance across bacteriorhodopsin, induced by coupling to Pt nanoparticles. J. Phys. Chem. Lett. 1, 3072–3077 (2010).

    Article  CAS  Google Scholar 

  26. Mikayama, T. et al. The electronic behavior of a photosynthetic reaction center monitored by conductive atomic force microscopy. J. Nanosci. Nanotechnol. 9, 97–107 (2009).

    Article  CAS  Google Scholar 

  27. Ron, I., Pecht, I., Sheves, M. & Cahen, D. Proteins as solid-state electronic conductors. Acc. Chem. Res. 7, 945–953 (2010).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported by the DFG via SPP 1243 (grants HO 3324/2 and RE 2592/2), COST-Phototech, the China Scholarship Council, the Nanosystems Initiative Munich (NIM), the Munich Center for Advanced Photonics (MAP), ERC Advanced Grant MolArt (no. 47299) and the Center of NanoScience (CeNS) in Munich. The authors thank A. Brenneis for technical assistance.

Author information

Authors and Affiliations

Authors

Contributions

D.G. and H.B. performed the experiments and analysed the data. I.C. produced the PS I mutants and self-assembly techniques, and introduced the theory. A.W.H. supervised sample preparation. J.R. supervised the photocurrent experiments. S.M.K. prepared the PS I substrates. I.C., I.V.F., A.W.H. and S.S. performed preliminary atomic force microscopy and scanning tunnelling microscopy measurements. J.R. and I.C. conceived the study and co-wrote the paper with A.W.H., J.V.B. and I.V.F.

Corresponding authors

Correspondence to Joachim Reichert or Itai Carmeli.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 1383 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Gerster, D., Reichert, J., Bi, H. et al. Photocurrent of a single photosynthetic protein. Nature Nanotech 7, 673–676 (2012). https://doi.org/10.1038/nnano.2012.165

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2012.165

This article is cited by

Search

Quick links

Nature Briefing: Translational Research

Sign up for the Nature Briefing: Translational Research newsletter — top stories in biotechnology, drug discovery and pharma.

Get what matters in translational research, free to your inbox weekly. Sign up for Nature Briefing: Translational Research