1 research outputs found
Spectroscopic Evidence for a Redox-Controlled Proton Gate at Tyrosine D in Photosystem II
Tyrosine D (TyrD) is one of two well-studied
redox active tyrosines
in Photosystem II. TyrD shows redox kinetics much slower than that
of its homologue, TyrZ, and is normally present as a stable deprotonated
radical (TyrD<sup>•</sup>). We have used time-resolved continuous
wave electron paramagnetic resonance and electron spin echo envelope
modulation spectroscopy to show that deuterium exchangeable protons
can access TyrD on a time scale that is much faster (50–100
times) than that previously observed. The time of H/D exchange is
strongly dependent on the redox state of TyrD. This finding can be
related to a change in position of a water molecule close to TyrD