Tracing of backward energy transfer from LH1 to LH2 in photosynthetic membranes grown under high and low irradiation.
1 IMDEA Nanoscience, 28049 Cantoblanco, Spain
2 Faculty of Medicine, University of Glasgow, Glasgow G12 8QQ, United Kingdom
3 Institute for Molecular Biology, University of Glasgow, Glasgow G12 8TA, United Kingdom
4 CNR-IFN, Dipartimento di Fisica, Politecnico di Milano, 20133 Milan, Italy
5 Italian Institute of Technology, Center forNanoScience and Technology at Politecnico di Milano, 20133 Milan, Italy
6 Ma Chung Research Center for Photosynthetic Pigments, Ma Chung University, Malang 65151, Indonesia
7 Department of Material Science, Università di Milano Bicocca, 20125 Milan, Italy
By introducing derivative transient absorption spectroscopy, we obtain rate constants for backward and forward energy transfer between LH1 and LH2 complexes in purple bacterial membranes. We find that backward energy transfer is strongly reduced in membranes grown under low irradiation conditions, compared to high light grown ones. We conclude that backward energy transfer is managed actively by the bacteria to avoid LH1 exciton deactivation under high irradiation conditions. The analytical method is generally applicable to excitonically coupled systems.
© Owned by the authors, published by EDP Sciences, 2013
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