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Two mechanisms for dissipation of excess light in monomeric and trimeric light-harvesting complexes

Dall'Osto, Luca; Cazzaniga, Stefano; Bressan, Mauro; Paleček, David LU ; Židek, Karel LU ; Niyogi, Krishna K.; Fleming, Graham R.; Zigmantas, Donatas LU and Bassi, Roberto (2017) In Nature Plants 3.
Abstract

Oxygenic photoautotrophs require mechanisms for rapidly matching the level of chlorophyll excited states from light harvesting with the rate of electron transport from water to carbon dioxide. These photoprotective reactions prevent formation of reactive excited states and photoinhibition. The fastest response to excess illumination is the so-called non-photochemical quenching which, in higher plants, requires the luminal pH sensor PsbS and other yet unidentified components of the photosystem II antenna. Both trimeric light-harvesting complex II (LHCII) and monomeric LHC proteins have been indicated as site(s) of the heat-dissipative reactions. Different mechanisms have been proposed: Energy transfer to a lutein quencher in trimers,... (More)

Oxygenic photoautotrophs require mechanisms for rapidly matching the level of chlorophyll excited states from light harvesting with the rate of electron transport from water to carbon dioxide. These photoprotective reactions prevent formation of reactive excited states and photoinhibition. The fastest response to excess illumination is the so-called non-photochemical quenching which, in higher plants, requires the luminal pH sensor PsbS and other yet unidentified components of the photosystem II antenna. Both trimeric light-harvesting complex II (LHCII) and monomeric LHC proteins have been indicated as site(s) of the heat-dissipative reactions. Different mechanisms have been proposed: Energy transfer to a lutein quencher in trimers, formation of a zeaxanthin radical cation in monomers. Here, we report on the construction of a mutant lacking all monomeric LHC proteins but retaining LHCII trimers. Its non-photochemical quenching induction rate was substantially slower with respect to the wild type. A carotenoid radical cation signal was detected in the wild type, although it was lost in the mutant. We conclude that non-photochemical quenching is catalysed by two independent mechanisms, with the fastest activated response catalysed within monomeric LHC proteins depending on both zeaxanthin and lutein and on the formation of a radical cation. Trimeric LHCII was responsible for the slowly activated quenching component whereas inclusion in supercomplexes was not required. This latter activity does not depend on lutein nor on charge transfer events, whereas zeaxanthin was essential.

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organization
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publication status
published
subject
in
Nature Plants
volume
3
external identifiers
  • scopus:85017405796
  • wos:000404896700001
ISSN
2055-0278
DOI
10.1038/nplants.2017.33
language
English
LU publication?
yes
id
a6112f03-4cb8-415f-8d0f-655701586b3d
date added to LUP
2017-04-26 14:15:39
date last changed
2017-09-18 13:33:19
@article{a6112f03-4cb8-415f-8d0f-655701586b3d,
  abstract     = {<p>Oxygenic photoautotrophs require mechanisms for rapidly matching the level of chlorophyll excited states from light harvesting with the rate of electron transport from water to carbon dioxide. These photoprotective reactions prevent formation of reactive excited states and photoinhibition. The fastest response to excess illumination is the so-called non-photochemical quenching which, in higher plants, requires the luminal pH sensor PsbS and other yet unidentified components of the photosystem II antenna. Both trimeric light-harvesting complex II (LHCII) and monomeric LHC proteins have been indicated as site(s) of the heat-dissipative reactions. Different mechanisms have been proposed: Energy transfer to a lutein quencher in trimers, formation of a zeaxanthin radical cation in monomers. Here, we report on the construction of a mutant lacking all monomeric LHC proteins but retaining LHCII trimers. Its non-photochemical quenching induction rate was substantially slower with respect to the wild type. A carotenoid radical cation signal was detected in the wild type, although it was lost in the mutant. We conclude that non-photochemical quenching is catalysed by two independent mechanisms, with the fastest activated response catalysed within monomeric LHC proteins depending on both zeaxanthin and lutein and on the formation of a radical cation. Trimeric LHCII was responsible for the slowly activated quenching component whereas inclusion in supercomplexes was not required. This latter activity does not depend on lutein nor on charge transfer events, whereas zeaxanthin was essential.</p>},
  articleno    = {17033},
  author       = {Dall'Osto, Luca and Cazzaniga, Stefano and Bressan, Mauro and Paleček, David and Židek, Karel and Niyogi, Krishna K. and Fleming, Graham R. and Zigmantas, Donatas and Bassi, Roberto},
  issn         = {2055-0278},
  language     = {eng},
  month        = {04},
  series       = {Nature Plants},
  title        = {Two mechanisms for dissipation of excess light in monomeric and trimeric light-harvesting complexes},
  url          = {http://dx.doi.org/10.1038/nplants.2017.33},
  volume       = {3},
  year         = {2017},
}