Abstract
The triplet state in PS II forms on one of the two accessary chloropylls, that was confirmed by EPR study of oriented membranes. Each accesssory chlorophyll belongs to D1 and D2 proteins, respectively. However which chlorophyll is active has not yet been determined. Pulsed EPR detects the dipolar interaction between a radical pair from which the distance ican be derived.
This work reports the result of ESEEM study of D1D2Cytb559 reaction center complexes with an acceptor quinone DMBIM reconstituted. The reduced quinone forms spin polarized signal induced by the tirplet state synchronized with laser flash. The obtained distance of 26 A is ascribed to the triplet state on the D1 protein and the reduced quinone.
