Charge separation in the reaction center of photosystem II studied as a function of temperature

摘要

In photosystem II of green plants the key photosynthetic reaction consists of the transfer of an electron from the primary donor called P680 to a nearby pheophytin molecule. We analyzed the temperature dependence of this reaction by subpicosecond transient absorption spectroscopy over the temperature range 20-240 K using isolated photo- system II reaction centers from spinach. After excitation in the red edge of the Q_y absorption band, the decay of the excited state can conveniently be described by two kinetic components that both accelerate with temperature.