RED ABSORPTION CHANGES ACCOMPANYING ELECTRON TRANSFER FROM A_1 TO THE IRON-SULFUR CLUSTERS IN PHOTOSYSTEM I

摘要

Forward electron transfer from the secondary electron acceptor(s) A_1 (phylloquinone) to the [4Fe-4S] clusters F_X, F_A and F_B in photosystem I (PS I) was previously studied, i.a., by transient absorption spectroscopy in the near UV and blue/green spectral regions where reduction of these cofactors changes their absorption spectra. The reoxidation kinetics of A_1~- was found to be bi-phasic with half-life times in the order of 10 ns and 200 ns (reviewed by Brettel & Leibl 2001).