Nanosecond Time Resolved Magnetic Resonance Spectra of P/Sup F/ in R. Sphaeroides and in R. Viridis Reaction Centers. Orientation of the Primary Donor in Single Crystals of R. Viridis Reaction Center

摘要

Photoexcitation of the reaction center protein from purple photosynthetic bacteria results in rapid (< 5 ps) formation of a radical pair, P/sup F/ composed of an oxidized bacteriochlorophyll a dimer, P exp + and a reduced bacteriopheophytin a, I exp - . The recent crystallization of the reaction center protein from R. viridis enables us to use magnetic resonance to obtain structural information about the reaction center relatively rapidly. We have grown large numbers of R. viridis reaction center crystals and have determined the orientation of the triplet axis system of the primary donor to within + 1 degree as well as a number of magnetically non-equivalent donor sites in the crystal. (ERA citation 09:008568)