Spectrally decomposed dark-to-light transitions in Synechocystis sp. PCC 6803

Alonso M. Acuña, Pascal van Alphen, Filipe Branco Dos Santos, Rienk van Grondelle, Klaas J. Hellingwerf, Ivo H.M. van Stokkum

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Photosynthetic activity and respiration share the thylakoid membrane in cyanobacteria. We present a series of spectrally resolved fluorescence experiments where whole cells of the cyanobacterium Synechocystis sp. PCC 6803 and mutants thereof underwent a dark-to-light transition after different dark-adaptation (DA) periods. Two mutants were used: (i) a PSI-lacking mutant (ΔPSI) and (ii) M55, a mutant without NAD(P)H dehydrogenase type-1 (NDH-1). For comparison, measurements of the wild-type were also carried out. We recorded spectrally resolved fluorescence traces over several minutes with 100 ms time resolution. The excitation light was at 590 nm so as to specifically excite the phycobilisomes. In ΔPSI, DA time has no influence, and in dichlorophenyl-dimethylurea (DCMU)-treated samples we identify three main fluorescent components: PB–PSII complexes with closed (saturated) RCs, a quenched or open PB–PSII complex, and a PB–PSII ‘not fully closed.’ For the PSI-containing organisms without DCMU, we conclude that mainly three species contribute to the signal: a PB–PSII–PSI megacomplex with closed PSII RCs and (i) slow PB → PSI energy transfer, or (ii) fast PB → PSI energy transfer and (iii) complexes with open (photochemically quenched) PSII RCs. Furthermore, their time profiles reveal an adaptive response that we identify as a state transition. Our results suggest that deceleration of the PB → PSI energy transfer rate is the molecular mechanism underlying a state 2 to state 1 transition.

Original languageEnglish
Pages (from-to)1-14
Number of pages14
JournalPhotosynthesis Research
DOIs
Publication statusE-pub ahead of print - 29 Mar 2018

Fingerprint

Synechocystis sp. PCC 6803
Synechocystis
Energy Transfer
Energy transfer
Dark Adaptation
energy transfer
Cyanobacteria
dark adaptation
Light
mutants
Phycobilisomes
Fluorescence
Thylakoids
Deceleration
fluorescence
phycobilisome
NAD
NAD(P)H dehydrogenase (quinone)
Oxidoreductases
Respiration

Keywords

  • Cyanobacteria
  • Cyclic electron flow
  • Plastoquinone pool
  • Singular value decomposition
  • Spectrally resolved fluorometry
  • Time-resolved spectroscopy

Cite this

Acuña, Alonso M. ; van Alphen, Pascal ; Branco Dos Santos, Filipe ; van Grondelle, Rienk ; Hellingwerf, Klaas J. ; van Stokkum, Ivo H.M. / Spectrally decomposed dark-to-light transitions in Synechocystis sp. PCC 6803. In: Photosynthesis Research. 2018 ; pp. 1-14.
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abstract = "Photosynthetic activity and respiration share the thylakoid membrane in cyanobacteria. We present a series of spectrally resolved fluorescence experiments where whole cells of the cyanobacterium Synechocystis sp. PCC 6803 and mutants thereof underwent a dark-to-light transition after different dark-adaptation (DA) periods. Two mutants were used: (i) a PSI-lacking mutant (ΔPSI) and (ii) M55, a mutant without NAD(P)H dehydrogenase type-1 (NDH-1). For comparison, measurements of the wild-type were also carried out. We recorded spectrally resolved fluorescence traces over several minutes with 100 ms time resolution. The excitation light was at 590 nm so as to specifically excite the phycobilisomes. In ΔPSI, DA time has no influence, and in dichlorophenyl-dimethylurea (DCMU)-treated samples we identify three main fluorescent components: PB–PSII complexes with closed (saturated) RCs, a quenched or open PB–PSII complex, and a PB–PSII ‘not fully closed.’ For the PSI-containing organisms without DCMU, we conclude that mainly three species contribute to the signal: a PB–PSII–PSI megacomplex with closed PSII RCs and (i) slow PB → PSI energy transfer, or (ii) fast PB → PSI energy transfer and (iii) complexes with open (photochemically quenched) PSII RCs. Furthermore, their time profiles reveal an adaptive response that we identify as a state transition. Our results suggest that deceleration of the PB → PSI energy transfer rate is the molecular mechanism underlying a state 2 to state 1 transition.",
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Spectrally decomposed dark-to-light transitions in Synechocystis sp. PCC 6803. / Acuña, Alonso M.; van Alphen, Pascal; Branco Dos Santos, Filipe; van Grondelle, Rienk; Hellingwerf, Klaas J.; van Stokkum, Ivo H.M.

In: Photosynthesis Research, 29.03.2018, p. 1-14.

Research output: Contribution to JournalArticleAcademicpeer-review

TY - JOUR

T1 - Spectrally decomposed dark-to-light transitions in Synechocystis sp. PCC 6803

AU - Acuña, Alonso M.

AU - van Alphen, Pascal

AU - Branco Dos Santos, Filipe

AU - van Grondelle, Rienk

AU - Hellingwerf, Klaas J.

AU - van Stokkum, Ivo H.M.

PY - 2018/3/29

Y1 - 2018/3/29

N2 - Photosynthetic activity and respiration share the thylakoid membrane in cyanobacteria. We present a series of spectrally resolved fluorescence experiments where whole cells of the cyanobacterium Synechocystis sp. PCC 6803 and mutants thereof underwent a dark-to-light transition after different dark-adaptation (DA) periods. Two mutants were used: (i) a PSI-lacking mutant (ΔPSI) and (ii) M55, a mutant without NAD(P)H dehydrogenase type-1 (NDH-1). For comparison, measurements of the wild-type were also carried out. We recorded spectrally resolved fluorescence traces over several minutes with 100 ms time resolution. The excitation light was at 590 nm so as to specifically excite the phycobilisomes. In ΔPSI, DA time has no influence, and in dichlorophenyl-dimethylurea (DCMU)-treated samples we identify three main fluorescent components: PB–PSII complexes with closed (saturated) RCs, a quenched or open PB–PSII complex, and a PB–PSII ‘not fully closed.’ For the PSI-containing organisms without DCMU, we conclude that mainly three species contribute to the signal: a PB–PSII–PSI megacomplex with closed PSII RCs and (i) slow PB → PSI energy transfer, or (ii) fast PB → PSI energy transfer and (iii) complexes with open (photochemically quenched) PSII RCs. Furthermore, their time profiles reveal an adaptive response that we identify as a state transition. Our results suggest that deceleration of the PB → PSI energy transfer rate is the molecular mechanism underlying a state 2 to state 1 transition.

AB - Photosynthetic activity and respiration share the thylakoid membrane in cyanobacteria. We present a series of spectrally resolved fluorescence experiments where whole cells of the cyanobacterium Synechocystis sp. PCC 6803 and mutants thereof underwent a dark-to-light transition after different dark-adaptation (DA) periods. Two mutants were used: (i) a PSI-lacking mutant (ΔPSI) and (ii) M55, a mutant without NAD(P)H dehydrogenase type-1 (NDH-1). For comparison, measurements of the wild-type were also carried out. We recorded spectrally resolved fluorescence traces over several minutes with 100 ms time resolution. The excitation light was at 590 nm so as to specifically excite the phycobilisomes. In ΔPSI, DA time has no influence, and in dichlorophenyl-dimethylurea (DCMU)-treated samples we identify three main fluorescent components: PB–PSII complexes with closed (saturated) RCs, a quenched or open PB–PSII complex, and a PB–PSII ‘not fully closed.’ For the PSI-containing organisms without DCMU, we conclude that mainly three species contribute to the signal: a PB–PSII–PSI megacomplex with closed PSII RCs and (i) slow PB → PSI energy transfer, or (ii) fast PB → PSI energy transfer and (iii) complexes with open (photochemically quenched) PSII RCs. Furthermore, their time profiles reveal an adaptive response that we identify as a state transition. Our results suggest that deceleration of the PB → PSI energy transfer rate is the molecular mechanism underlying a state 2 to state 1 transition.

KW - Cyanobacteria

KW - Cyclic electron flow

KW - Plastoquinone pool

KW - Singular value decomposition

KW - Spectrally resolved fluorometry

KW - Time-resolved spectroscopy

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SN - 0166-8595

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