2021年11月15日
Excitation-energy transfer in heterocysts isolated from the cyanobacterium Anabaena sp. PCC 7120 as studied by time-resolved fluorescence spectroscopy.
Biochimica et biophysica acta. Bioenergetics
- 巻
- 1863
- 号
- 1
- 開始ページ
- 148509
- 終了ページ
- 148509
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1016/j.bbabio.2021.148509
Heterocysts are formed in filamentous heterocystous cyanobacteria under nitrogen-starvation conditions, and possess a very low amount of photosystem II (PSII) complexes than vegetative cells. Molecular, morphological, and biochemical characterizations of heterocysts have been investigated; however, excitation-energy dynamics in heterocysts are still unknown. In this study, we examined excitation-energy-relaxation processes of pigment-protein complexes in heterocysts isolated from the cyanobacterium Anabaena sp. PCC 7120. Thylakoid membranes from the heterocysts showed no oxygen-evolving activity under our experimental conditions and no thermoluminescence-glow curve originating from charge recombination of S2QA-. Two dimensional blue-native/SDS-PAGE analysis exhibits tetrameric, dimeric, and monomeric PSI complexes but almost no dimeric and monomeric PSII complexes in the heterocyst thylakoids. The steady-state fluorescence spectrum of the heterocyst thylakoids at 77 K displays both characteristic PSI fluorescence and unusual PSII fluorescence different from the fluorescence of PSII dimer and monomer complexes. Time-resolved fluorescence (TRF) spectra at 77 K, followed by fluorescence decay-associated spectra, showed different PSII and PSI fluorescence bands between heterocysts and vegetative thylakoids. Based on these findings, we discuss the excitation-energy-transfer mechanism in the heterocysts.
- リンク情報
- ID情報
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- DOI : 10.1016/j.bbabio.2021.148509
- PubMed ID : 34793768