Mechanism of proton release during water oxidation in Photosystem II.

Photosystem II (PSII) catalyzes light-driven water oxidation that releases dioxygen into our atmosphere and provides the electrons needed for the synthesis of biomass. The catalysis occurs in the oxygen-evolving oxo-manganese-calcium (MnOCa) cluster that drives the oxidation and deprotonation of substrate water molecules leading to the O formation. However, despite recent advances, the mechanism of these reactions remains unclear and much debated.

A pyroxene-based quantum magnet with multiple magnetization plateaus.

Pyroxenes (AMXO) consisting of infinite one-dimensional edge-sharing MO chains and bridging XO tetrahedra are fertile ground for finding quantum materials. Thus, here, we have studied calcium cobalt germanate (CaCoGeO) and calcium cobalt silicate (CaCoSiO) crystals in depth. Heat capacity data show that the spins in both compounds are dominantly Ising-like, even after being manipulated by high magnetic fields.

In vivo ElectroChromic Shift measurements of photosynthetic activity in far-red absorbing cyanobacteria.

Some cyanobacteria can do photosynthesis using not only visible but also far-red light that is unused by most other oxygenic photoautotrophs because of its lower energy content. These species have a modified photosynthetic apparatus containing red-shifted pigments. The incorporation of red-shifted pigments decreases the photochemical efficiency of photosystem I and, especially, photosystem II, and it might affect the distribution of excitation energy between the two photosystems with possible consequences on the activity of the entire electron transport chain.