Primary Reactions of Photosynthesis: a Personal View

Photosystem I of oxygenic photosynthesis is reviewed. The article describes historical as well as personal accounts on P700, P430 and chlorophyll a\u27 besides other topics. The 1971 discovery of P430 was rather accidental in the course of a P700 investigation, which also yielded extinction coefficients of P430 and P700, together with their difference spectra. The author later conducted EPR experiments to prove that P430 is A2 (FeSx: Component X), which has, unfortunately, not been accepted well yet. The author\u27s reconstitution experiment of P700 with PsaA/B apoprotein and chlorophyll a\u27 in 1986 has only recently been realized when a three dimensional structure of Photosystem I complex was presented in 2001