Tracking the first electron transfer step at the donor side of oxygen-evolving photosystem II by time-resolved infrared spectroscopy.

ABSTRACT: In oxygen-evolving photosystem II (PSII), the multi-phasic electron transfer from a redox-active tyrosine residue (TyrZ) to a chlorophyll cation radical (P680⁺) precedes the water-oxidation chemistry of the S-state cycle of the Mn₄Ca cluster. Here we investigate these early events, observable within about 10 ns to 10 ms after laser-flash excitation, by time-resolved single-frequency infrared (IR) spectroscopy in the spectral range of 1310-1890 cm^-1 for oxygen-evolving PSII membrane particles from spinach. Comparing the IR difference spectra at 80 ns, 500 ns, and 10 µs allowed for the identification of quinone, P680 and TyrZ contributions. A broad electronic absorption band assignable P680⁺ was used to trace largely specifically the P680⁺

SUBMITTER: Dekmak MY 

PROVIDER: S-EPMC11615052 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature