Oxygen drives a rapid, reversible photoprotective switch in photosynthetic antennae

Oxygen is the archetypal agent of photooxidative damage, and it is generally countered by removing its reactive products or by regulated, energy-costly responses. We show that in photosynthetic light-harvesting complexes, oxygen also drives a rapid, reversible photoprotective switch. Using a new bulk fluorescence method that separates reversible dark states from irreversible photobleaching, together with single-molecule spectroscopy, we find that illumination and oxygen generate a reversible, protein-stabilized charge-separated state comprising oxidized chlorophyll and superoxide. Access to this state increasingly outcompetes irreversible photodamage as excitation intensity falls to physiological levels and is strongly accelerated by ascorbic acid in native thylakoid membranes. These findings identify a constitutive oxygen-dependent photoprotective pathway and suggest that redox-state recovery can determine whether oxygen-associated chemistry protects or damages photoactive systems.

Authors

Institutions

Publication Details

Journal
bioRxiv (Cold Spring Harbor Laboratory)
Published
2026-10-30
DOI
https://doi.org/10.64898/2026.10.28.762473
Primary Topic
Photosynthetic Processes and Mechanisms
Type
preprint

Funders

Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
preprint

Oxygen drives a rapid, reversible photoprotective switch in photosynthetic antennae

Alastair Thomas Gardiner, Michal Gwizdala, Bertus van Heerden, Artur Osyczka et al.
bioRxiv (Cold Spring Harbor Laboratory)
Photosynthetic Processes and Mechanisms
preprint

Oxygen drives a rapid, reversible photoprotective switch in photosynthetic antennae

Alastair Thomas Gardiner, Michal Gwizdala, Bertus van Heerden, Artur Osyczka, Marcin Sarewicz, Tjaart P. J. Krüger, Richard John Cogdell, Farooq Kyeyune, Sabera Millan, Francois Conradie
preprint en

Abstract

Oxygen is the archetypal agent of photooxidative damage, and it is generally countered by removing its reactive products or by regulated, energy-costly responses. We show that in photosynthetic light-harvesting complexes, oxygen also drives a rapid, reversible photoprotective switch. Using a new bulk fluorescence method that separates reversible dark states from irreversible photobleaching, together with single-molecule spectroscopy, we find that illumination and oxygen generate a reversible, protein-stabilized charge-separated state comprising oxidized chlorophyll and superoxide. Access to this state increasingly outcompetes irreversible photodamage as excitation intensity falls to physiological levels and is strongly accelerated by ascorbic acid in native thylakoid membranes. These findings identify a constitutive oxygen-dependent photoprotective pathway and suggest that redox-state recovery can determine whether oxygen-associated chemistry protects or damages photoactive systems.

bioRxiv (Cold Spring Harbor Laboratory)
Jagiellonian University (PL), University of Pretoria (ZA), University of Glasgow (GB)
U.S. Department of Energy, National Research Foundation, Council for Scientific and Industrial Research, South Africa, University of Pretoria, Directorate for Biological Sciences, Office of Science, Biotechnology and Biological Sciences Research Council, Basic Energy Sciences
Photosynthetic Processes and Mechanisms
DOIOpen Access PDFOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.

Laika access coming soon