Magnetic susceptibility of the non-heme iron in photosystem II

The magnetic susceptibility of the non-heme iron in plant photosystem II was first measured by a highly sensitive magnetometer equipped with a pulsed magnetic field. From the temperature dependence of the paramagnetic susceptibility of the non-heme ferrous iron with S = 2, the zero-field interaction parameters D and E were determined to be 5.5 +/- 1.0 and 0.75 +/- 0.75 cm(-1) respectively. These values are almost the same as those observed in a purple photosynthetic bacterium Rhodobacter sphaeroides, suggesting that the structure of the acceptor side of plant photosystem II is also similar to that of the purple photosynthetic bacterium.