Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction

Abstract Photosystem II (PSII) catalyses the photoinduced oxygen evolution and, by producing reducing equivalents drives, in concert with PSI, the conversion of carbon dioxide to sugars. Our knowledge about the architecture of the reaction centre (RC) complex and the mechanisms of charge separation...

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Autores principales:	Melinda Magyar, Gábor Sipka, László Kovács, Bettina Ughy, Qingjun Zhu, Guangye Han, Vladimír Špunda, Petar H. Lambrev, Jian-Ren Shen, Győző Garab
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/a8cd09bca7e94f0295c45c3ff6448098
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spelling	oai:doaj.org-article:a8cd09bca7e94f0295c45c3ff64480982021-12-02T15:09:06ZRate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction10.1038/s41598-018-21195-22045-2322https://doaj.org/article/a8cd09bca7e94f0295c45c3ff64480982018-02-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-21195-2https://doaj.org/toc/2045-2322Abstract Photosystem II (PSII) catalyses the photoinduced oxygen evolution and, by producing reducing equivalents drives, in concert with PSI, the conversion of carbon dioxide to sugars. Our knowledge about the architecture of the reaction centre (RC) complex and the mechanisms of charge separation and stabilisation is well advanced. However, our understanding of the processes associated with the functioning of RC is incomplete: the photochemical activity of PSII is routinely monitored by chlorophyll-a fluorescence induction but the presently available data are not free of controversy. In this work, we examined the nature of gradual fluorescence rise of PSII elicited by trains of single-turnover saturating flashes (STSFs) in the presence of a PSII inhibitor, permitting only one stable charge separation. We show that a substantial part of the fluorescence rise originates from light-induced processes that occur after the stabilisation of charge separation, induced by the first STSF; the temperature-dependent relaxation characteristics suggest the involvement of conformational changes in the additional rise. In experiments using double flashes with variable waiting times (∆τ) between them, we found that no rise could be induced with zero or short ∆τ, the value of which depended on the temperature - revealing a previously unknown rate-limiting step in PSII.Melinda MagyarGábor SipkaLászló KovácsBettina UghyQingjun ZhuGuangye HanVladimír ŠpundaPetar H. LambrevJian-Ren ShenGyőző GarabNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-9 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Melinda Magyar Gábor Sipka László Kovács Bettina Ughy Qingjun Zhu Guangye Han Vladimír Špunda Petar H. Lambrev Jian-Ren Shen Győző Garab Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction
description	Abstract Photosystem II (PSII) catalyses the photoinduced oxygen evolution and, by producing reducing equivalents drives, in concert with PSI, the conversion of carbon dioxide to sugars. Our knowledge about the architecture of the reaction centre (RC) complex and the mechanisms of charge separation and stabilisation is well advanced. However, our understanding of the processes associated with the functioning of RC is incomplete: the photochemical activity of PSII is routinely monitored by chlorophyll-a fluorescence induction but the presently available data are not free of controversy. In this work, we examined the nature of gradual fluorescence rise of PSII elicited by trains of single-turnover saturating flashes (STSFs) in the presence of a PSII inhibitor, permitting only one stable charge separation. We show that a substantial part of the fluorescence rise originates from light-induced processes that occur after the stabilisation of charge separation, induced by the first STSF; the temperature-dependent relaxation characteristics suggest the involvement of conformational changes in the additional rise. In experiments using double flashes with variable waiting times (∆τ) between them, we found that no rise could be induced with zero or short ∆τ, the value of which depended on the temperature - revealing a previously unknown rate-limiting step in PSII.
format	article
author	Melinda Magyar Gábor Sipka László Kovács Bettina Ughy Qingjun Zhu Guangye Han Vladimír Špunda Petar H. Lambrev Jian-Ren Shen Győző Garab
author_facet	Melinda Magyar Gábor Sipka László Kovács Bettina Ughy Qingjun Zhu Guangye Han Vladimír Špunda Petar H. Lambrev Jian-Ren Shen Győző Garab
author_sort	Melinda Magyar
title	Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction
title_short	Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction
title_full	Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction
title_fullStr	Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction
title_full_unstemmed	Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction
title_sort	rate-limiting steps in the dark-to-light transition of photosystem ii - revealed by chlorophyll-a fluorescence induction
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/a8cd09bca7e94f0295c45c3ff6448098
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Rate-limiting steps in the dark-to-light transition of Photosystem II - revealed by chlorophyll-a fluorescence induction

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