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Updated: Jul 5, 2025

Isolation and Characterization of Intact Phycobilisome in Cyanobacteria
Published on: November 10, 2021
Energy transfer from phycobilisomes to photosystem I at room temperature
Avratanu Biswas1,2,3, Parveen Akhtar2, Petar H Lambrev2
1Department of Physics and Astronomy and LaserLaB, Faculty of Science, Vrije Universiteit Amsterdam, Amsterdam, Netherlands.
Abstract:
The phycobilisomes function as the primary light-harvesting antennae in cyanobacteria and red algae, effectively harvesting and transferring excitation energy to both photosystems. Here we investigate the direct energy transfer route from the phycobilisomes to photosystem I at room temperature in a mutant of the cyanobacterium Synechocystis sp. PCC 6803 that lacks photosystem II. The excitation dynamics are studied by picosecond time-resolved fluorescence measurements in combination with global and target analysis. Global analysis revealed several fast equilibration time scales and a decay of the equilibrated system with a time constant of ≈220 ps. From simultaneous target analysis of measurements with two different excitations of 400 nm (chlorophyll a) and 580 nm (phycobilisomes) a transfer rate of 42 ns-1 from the terminal emitter of the phycobilisome to photosystem I was estimated.
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