Diatoms are a group of marine algae that are responsible for a significant part of global oxygen production. Adapted to life in an aqueous environment dominated by the blue–green light, their major light-harvesting antennae—fucoxanthin–chlorophyll protein complexes (FCPs)—exhibit different pigment compositions than of plants. Despite extensive experimental studies, until recently the theoretical description of excitation energy dynamics in these complexes was limited by the lack of high-resolution structural data. In this work, we use the recently resolved crystallographic information of the FCP complex from Phaeodactylum tricornutum diatom [Wang et al., Science 363, 6427 (2019)] and quantum chemistry-based calculations to evaluate the chlorophyll transition dipole moments, atomic transition charges from electrostatic potential, and the inter-chlorophyll couplings in this complex. The obtained structure-based excitonic couplings form the foundation for any modeling of stationary or time-resolved spectroscopic data. We also calculate the inter-pigment Förster energy transfer rates and identify two quickly equilibrating chlorophyll clusters.
Structure-based model of fucoxanthin–chlorophyll protein complex: Calculations of chlorophyll electronic couplings
Note: This paper is part of the JCP Special Topic on Photosynthetic Light-Harvesting and Energy Conversion.
Austėja Mikalčiūtė, Andrius Gelzinis, Mindaugas Mačernis, Claudia Büchel, Bruno Robert, Leonas Valkunas, Jevgenij Chmeliov; Structure-based model of fucoxanthin–chlorophyll protein complex: Calculations of chlorophyll electronic couplings. J. Chem. Phys. 21 June 2022; 156 (23): 234101. https://doi.org/10.1063/5.0092154
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