Long-lived quantum coherence in photosynthetic complexes at physiological temperature

Gitt Panitchayangkoon, Dugan Hayes, Kelly A. Fransted, Justin R. Caram, Elad Harel, Jianzhong Wen, Robert E. Blankenship, Gregory S. Engel

Research output: Contribution to journalArticle

731 Scopus citations

Abstract

Photosynthetic antenna complexes capture and concentrate solar radiation by transferring the excitation to the reaction center that stores energy from the photon in chemical bonds. This process occurs with near-perfect quantum efficiency. Recent experiments at cryogenic temperatures have revealed that coherent energy transfer - a wave-like transfer mechanism - occurs in many photosynthetic pigment-protein complexes. Using the Fenna-Matthews-Olson antenna complex (FMO) as a model system, theoretical studies incorporating both incoherent and coherent transfer as well as thermal dephasing predict that environmentally assisted quantum transfer efficiency peaks near physiological temperature; these studies also show that this mechanism simultaneously improves the robustness of the energy transfer process. This theory requires long-lived quantumcoherence at roomtemperature, which never has been observed in FMO. Here we present evidence that quantum coherence survives in FMO at physiological temperature for at least 300 fs, long enough to impact biological energy transport. These data prove that the wave-like energy transfer process discovered at 77 K is directly relevant to biological function. Microscopically, we attribute this long coherence lifetime to correlated motions within the protein matrix encapsulating the chromophores, and we find that the degree of protection afforded by the protein appears constant between 77 K and 277 K. The protein shapes the energy landscape and mediates an efficient energy transfer despite thermal fluctuations.

Original languageEnglish (US)
Pages (from-to)12766-12770
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume107
Issue number29
DOIs
StatePublished - Jul 20 2010

Keywords

  • Biophysics
  • Photosynthesis
  • Quantum beating
  • Quantum biology
  • Ultrafast spectroscopy

ASJC Scopus subject areas

  • General

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  • Cite this

    Panitchayangkoon, G., Hayes, D., Fransted, K. A., Caram, J. R., Harel, E., Wen, J., Blankenship, R. E., & Engel, G. S. (2010). Long-lived quantum coherence in photosynthetic complexes at physiological temperature. Proceedings of the National Academy of Sciences of the United States of America, 107(29), 12766-12770. https://doi.org/10.1073/pnas.1005484107