Sohoni, S., Wu, P.-J.E., Shen, Q. orcid.org/0000-0003-4660-0960 et al. (4 more authors) (2024) Resonant vibrational enhancement of downhill energy transfer in the C-phycocyanin chromophore dimer. The Journal of Physical Chemistry Letters, 15 (46). pp. 11569-11576. ISSN 1948-7185
Abstract
Energy transfer between electronically coupled photosynthetic light-harvesting antenna pigments is frequently assisted by protein and chromophore nuclear motion. This energy transfer mechanism usually occurs in the weak or intermediate system-bath coupling regime. Redfield theory is frequently used to describe the energy transfer in this regime. Spectral densities describe vibronic coupling in visible transitions of the chromophores and govern energy transfer in the Redfield mechanism. In this work, we perform finely sampled broadband pump-probe spectroscopy on the phycobilisome antenna complex with sub-10-fs pump and probe pulses. The spectral density obtained by Fourier transforming the pump-probe time-domain signal is used to perform modified Redfield rate calculations to check for vibrational enhancement of energy transfer in a coupled chromophore dimer in the C-phycocyanin protein of the phycobilisome antenna. We find two low-frequency vibrations to be in near-resonance with the interexcitonic energy gap and a few-fold enhancement in the interexcitonic energy transfer rate due to these resonances at room temperature. Our observations and calculations explain the fast downhill energy transfer process in C-phycocyanin. We also observe high-frequency vibrations involving chromophore-protein residue interactions in the excited state of the phycocyanobilin chromophore. We suggest that these vibrations lock the chromophore nuclear configuration of the excited state and prevent the energetic relaxation that blocks energy transfer.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Authors. This publication is licensed under CC-BY 4.0. https://creativecommons.org/licenses/by/4.0/ |
Keywords: | Chromophores; Energy; Energy transfer; Oligomers; Oscillation |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Biosciences (Sheffield) |
Funding Information: | Funder Grant number ROYAL SOCIETY URF\R1\191548 ROYAL SOCIETY URF\R\241006 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 15 Nov 2024 11:03 |
Last Modified: | 11 Mar 2025 10:57 |
Status: | Published |
Publisher: | American Chemical Society (ACS) |
Refereed: | Yes |
Identification Number: | 10.1021/acs.jpclett.4c02386 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:219681 |