Light-driven CO2 assimilation by photosystem II and its relation to photosynthesis

For natural oxygenic photosynthesis, there is a consensus that H2O is oxidized to molecular oxygen by photosystem II (PSII) in the grana, while CO2 assimilation takes place, long after oxygen evolu-tion, in light-independent reactions, for example, through the Calvin-Benson Cycle in the stroma. Here, we report, for the first time, light-driven CO2 assimilation by the PSII core complex, where the formation of methanol, along with the oxygen evolution, is validated by in -situ mass spectrometry, gas chromatography and isotopic labeling experiments. Such an unusual CO2 assimilation is likely to be a simultaneous event along with the usual electron transfer occurring in normal light-independent assimilation. This discovery is extraordinary and is of great significance as it may substantially modify our understanding of the mechanism of photosynthesis.(c) 2023, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

In a groundbreaking discovery, researchers have found that the PSII core complex can drive the assimilation of CO2 to produce methanol under light, challenging the conventional understanding of photosynthesis. This finding holds significant implications for our understanding of the mechanism behind photosynthesis.