Mechanism of photodamage of the oxygen evolving Mn Cluster of Photosystem II by excessive light energy

Alonso Zavafer, Wataru Koinuma, Wah Soon Chow, Mun Hon Cheah*, Hiroyuki Mino

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    29 Citations (Scopus)

    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.

    Original languageEnglish
    Article number7604
    JournalScientific Reports
    Volume7
    Issue number1
    DOIs
    Publication statusPublished - 1 Dec 2017

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