Does the Rapidly Metabolized 32 kDa Protein Carry the Reaction Center of PS II

The rapidly metabolized 32 kDa thylakoid membrane protein (RMP) which binds the secondary quinone electron acceptor (QB) as well as herbicides of several families (1) shows sequence homology to the L and M subunits of the bacterial photosynthetic reaction center complex (2,3). This gave rise to speculations on the same role for the QB protein and a 34 kDa protein, encoded by the so-called D-2 gene (4), both of chloro-plasts, and the L and M subunits of photosynthetic bacteria.