LIGHT-INDUCED CHARGE SEPARATION BETWEEN PLASTOCYANIN AND THE IRON-SULFUR CLUSTERS F-A AND F-B IN THE COMPLEX OF PLASTOCYANIN AND PHOTOSYSTEM-I

The light-induced electron transfer in a crosslinked complex between p lastocyanin and photosystem I from spinach was studied by EPR at low t emperature. Electron donation from reduced plastocyanin to P700(+) was observed under illumination above a temperature of about 160 K, resul ting in a second charge separation and an electron transfer from rered uced P700 to the terminal electron acceptors F-A/F-B The charge-separa ted state Pc(ox)P700(+)[F-A/F-B](2-) was found to be stable at 15 K, I mplications of these results for the kinetic constants of the donation reaction and the backtransfer of electrons from reduced accepters as well as for the structural models of the terminal accepters are discus sed. (C) 1996 Academic Press, Inc.