Modelling excitation energy transfer and trapping in the filamentous cyanobacterium Anabaena variabilis PCC 7120

Avratanu Biswas, Xinpeng Huang, Petar H. Lambrev, Ivo H.M. van Stokkum*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

The phycobilisome (PBS) serves as the major light-harvesting system, funnelling excitation energy to both photosystems (PS) in cyanobacteria and red algae. The picosecond kinetics involving the excitation energy transfer has been studied within the isolated systems and intact filaments of the cyanobacterium Anabaena variabilis PCC 7120. A target model is proposed which resolves the dynamics of the different chromophore groups. The energy transfer rate of 8.5 ± 1.0/ns from the rod to the core is the rate-limiting step, both in vivo and in vitro. The PBS-PSI-PSII supercomplex reveals efficient excitation energy migration from the low-energy allophycocyanin, which is the terminal emitter, in the PBS core to the chlorophyll a in the photosystems. The terminal emitter of the phycobilisome transfers energy to both PSI and PSII with a rate of 50 ± 10/ns, equally distributing the solar energy to both photosystems. Finally, the excitation energy is trapped by charge separation in the photosystems with trapping rates estimated to be 56 ± 6/ns in PSI and 14 ± 2/ns in PSII.

Original languageEnglish
Pages (from-to)261-272
Number of pages12
JournalPhotosynthesis Research
Volume144
Issue number2
Early online date19 Feb 2020
DOIs
Publication statusPublished - 1 May 2020

Keywords

  • Global analysis
  • Light harvesting
  • Photosystem I
  • Photosystem II
  • Phycobilisome
  • Target analysis

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