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Digitonin-sensitive LHCII enlarges the antenna of Photosystem I in stroma lamellae of Arabidopsis thaliana after far-red and blue-light treatment

Authors :
Rob B. M. Koehorst
Emilie Wientjes
Anniek Oosterwijk
Peter Bos
Herbert van Amerongen
Arjen N. Bader
John Philippi
Source :
Biochimica et Biophysica Acta-Bioenergetics 1860 (2019) 8, Biochimica et Biophysica Acta-Bioenergetics, 1860(8), 651-658
Publication Year :
2019

Abstract

Light drives photosynthesis. In plants it is absorbed by light-harvesting antenna complexes associated with Photosystem I (PSI) and photosystem II (PSII). As PSI and PSII work in series, it is important that the excitation pressure on the two photosystems is balanced. When plants are exposed to illumination that overexcites PSII, a special pool of the major light-harvesting complex LHCII is phosphorylated and moves from PSII to PSI (state 2). If instead PSI is over-excited the LHCII complex is dephosphorylated and moves back to PSII (state 1). Recent findings have suggested that LHCII might also transfer energy to PSI in state 1. In this work we used a combination of biochemistry and (time-resolved) fluorescence spectroscopy to investigate the PSI antenna size in state 1 and state 2 for Arabidopsis thaliana. Our data shows that 0.7 ± 0.1 unphosphorylated LHCII trimers per PSI are present in the stroma lamellae of state-1 plants. Upon transition to state 2 the antenna size of PSI in the stroma membrane increases with phosphorylated LHCIIs to a total of 1.2 ± 0.1 LHCII trimers per PSI. Both phosphorylated and unphosphorylated LHCII function as highly efficient PSI antenna.

Details

Language :
English
ISSN :
00052728
Volume :
1860
Issue :
8
Database :
OpenAIRE
Journal :
Biochimica et Biophysica Acta - Bioenergetics
Accession number :
edsair.doi.dedup.....315785081449b38bd8e559dfc373aaa3
Full Text :
https://doi.org/10.1016/j.bbabio.2019.07.001