Enhancing the spectral range of plant and bacterial light-harvesting pigment-protein complexes with various synthetic chromophores incorporated into lipid vesicles

Hancock, Ashley M., Swainsbury, David J. K., Meredith, Sophie A., Morigaki, Kenichi, Hunter, C. Neil and Adams, Peter G. (2022) Enhancing the spectral range of plant and bacterial light-harvesting pigment-protein complexes with various synthetic chromophores incorporated into lipid vesicles. Journal of Photochemistry and Photobiology B-Biology, 237. ISSN 1011-1344

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The Light-Harvesting (LH) pigment-protein complexes found in photosynthetic organisms have the role of absorbing solar energy with high efficiency and transferring it to reaction centre complexes. LH complexes contain a suite of pigments that each absorb light at specific wavelengths, however, the natural combinations of pigments within any one protein complex do not cover the full range of solar radiation. Here, we provide an in-depth comparison of the relative effectiveness of five different organic “dye” molecules (Texas Red, ATTO, Cy7, DiI, DiR) for enhancing the absorption range of two different LH membrane protein complexes (the major LHCII from plants and LH2 from purple phototrophic bacteria). Proteoliposomes were self-assembled from defined mixtures of lipids, proteins and dye molecules and their optical properties were quantified by absorption and fluorescence spectroscopy. Both lipid-linked dyes and alternative lipophilic dyes were found to be effective excitation energy donors to LH protein complexes, without the need for direct chemical or generic modification of the proteins. The Förster theory parameters (e.g., spectral overlap) were compared between each donor-acceptor combination and found to be good predictors of an effective dye-protein combination. At the highest dye-to-protein ratios tested (over 20:1), the effective absorption strength integrated over the full spectral range was increased to ~180% of its natural level for both LH complexes. Lipophilic dyes could be inserted into pre-formed membranes although their effectiveness was found to depend upon favourable physicochemical interactions. Finally, we demonstrated that these dyes can also be effective at increasing the spectral range of surface-supported models of photosynthetic membranes, using fluorescence microscopy. The results of this work provide insight into the utility of self-assembled lipid membranes and the great flexibility of LH complexes for interacting with different dyes.

Item Type: Article
Additional Information: Acknowledgements: A.M.H. was supported by a studentship from the Engineering and Physical Sciences Research Council (EPSRC, UK) (award number 1807029) and further EPSRC grants (EP/T013958/1 and EP/J017566/1). D.J.K.S. was supported by European Research Council Synergy Award 854126 and Biotechnology and Biological Sciences Research Council (BBSRC, UK) (BB/M000265/1). S.A.M. was supported by a BBSRC studentship (BB/M011151/1). K.M. was supported by the Japan-UK Research Cooperative Program (JPJSBP120195707) and a Grant-in-Aid for Scientific research (Kakenhi) (No. 19H04725 and 21KK0088) from Japan Society for the Promotion of Science (JSPS). C.N.H. was supported by European Research Council Synergy Award 854126. P.G.A. was supported by a University Academic Fellowship from the University of Leeds and a grant from the EPSRC (EP/T013958/1). The PicoQuant FLIM instrument at Leeds was acquired with funding from the BBSRC (BB/R000174/1).
Faculty \ School: Faculty of Science > School of Biological Sciences
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Depositing User: LivePure Connector
Date Deposited: 18 Oct 2022 13:32
Last Modified: 30 Mar 2024 08:31
URI: https://ueaeprints.uea.ac.uk/id/eprint/89148
DOI: 10.1016/j.jphotobiol.2022.112585


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