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bioRxiv · 10.1101/502450

Evolution of photochemical reaction centres: more twists?

Cardona, T.·Rutherford, A. W.
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Abstract

The earliest event recorded in the molecular evolution of photosynthesis is the structural and functional specialisation of Type I (ferredoxin-reducing) and Type II (quinone-reducing) reaction centres. Here we point out that the homodimeric Type I reaction centre of Heliobacteria has a Ca2+-binding site with a number of striking parallels to the Mn4CaO5 cluster of cyanobacterial Photosystem II. This structural parallels indicate that water oxidation chemistry originated at the divergence of Type I and Type II reaction centres. We suggests that this divergence was triggered by a structural rearrangement of a core transmembrane helix resulting in a shift of the redox potential of the electron donor side and electron acceptor side at the same time and in the same redox direction.

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Cardona, T., Rutherford, A. W.. 2018-12-20. Evolution of photochemical reaction centres: more twists?. https://doi.org/10.1101/502450

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