Abstract

Photodamage to Photosystem II (PSII) has been attributed either to excessive excitation of photosynthetic pigments or by direct of light absorption by Mn4CaO5 cluster. Here we investigated the time course of PSII photodamage and release of Mn in PSII-enriched membranes under high light illumination at 460 nm and 660 nm. We found that the loss of PSII activity, assayed by chlorophyll fluorescence, is faster than release of Mn from the Mn4CaO5 cluster, assayed by EPR. Loss of PSII activity and Mn release was slower during illumination in the presence of exogenous electron acceptors. Recovery of PSII activity was observed, after 30 min of addition of electron donor post illumination. The same behavior was observed under 460 and 660 nm illumination, suggesting stronger correlation between excessive excitation and photodamage compared to direct light absorption by the cluster. A unified model of PSII photodamage that takes into account present and previous literature reports is presented.

Details

Title
Mechanism of Photodamage of the Oxygen Evolving Mn Cluster of Photosystem II by Excessive Light Energy
Author
Alonso Zavafer 1   VIAFID ORCID Logo  ; Koinuma, Wataru 2 ; Chow, Wah Soon 1 ; Mun Hon Cheah 1   VIAFID ORCID Logo  ; Mino, Hiroyuki 2 

1  Australian National University, Research School of Biology, Canberra, Australia 
2  Division of Material Science (Physics), Graduate school of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Japan 
Pages
1-8
Publication year
2017
Publication date
Aug 2017
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
DOI
https://doi.org/10.1038/s41598-017-07671-1
ProQuest document ID
1957176406
Copyright
© 2017. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.