Bicarbonate is a key regulator but not a substrate for O evolution in Photosystem II.

Photosynth Res

Department of Biochemistry, Department of Plant Biology, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.

Published: October 2024


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Article Abstract

Photosystem II (PSII) uses light energy to oxidize water and to reduce plastoquinone in the photosynthetic electron transport chain. O is produced as a byproduct. While most members of the PSII research community agree that O originates from water molecules, alternative hypotheses involving bicarbonate persist in the literature. In this perspective, we provide an overview of the important roles of bicarbonate in regulating PSII activity and assembly. Further, we emphasize that biochemistry, spectroscopy, and structural biology experiments have all failed to detect bicarbonate near the active site of O evolution. While thermodynamic arguments for oxygen-centered bicarbonate oxidation are valid, the claim that bicarbonate is a substrate for photosynthetic O evolution is challenged.

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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11413114PMC
http://dx.doi.org/10.1007/s11120-024-01111-8DOI Listing

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