Molecular operation of metals into the function and state of photosystem II

Abstract

Action sites of different metals in the electron transport reactions of Photosystem II (PS II) evaluated by delayed fluorescence in the ms range (ms DF) and pigment–pigment, pigment–protein and protein–protein interaction states by electrophoretic measurements are presented. The main targets for the metals action were shown to be:

(i) Cd²⁺, Ni²⁺, Co²⁺–Y_z or CaMn₄-cluster on the donor site with dependence on pH;

(ii) Ni²⁺, Co²⁺, Zn²⁺, Al³⁺, Mn²⁺ between Q_A and Q_B on the acceptor site; effect of Al³⁺ and Mn²⁺ is observed only in acidic pH.

Investigated metals bring about monomerization of oligomeric and dimeric chlorophyll–protein complexes (CPC) and destabilization of protein–protein interactions. Molecular mechanisms of metals interference with the structure of PS II are discussed.