CIRCULAR-DICHROISM (CD) STUDY OF PERIDININ-CHLOROPHYLL A PROTEIN (PCP) COMPLEXES FROM MARINE DINOFLAGELLATE ALGAE - THE TETRAMER APPROACH

The absorption and circular dichroism spectra of PCP (peridinin-chloro phyll a protein) light-harvesting complexes from Glenodinium sp. and G onyaulax polyedra are studied in terms of vibronic coupling theory. An alysis based on a tetramer model allows the determination of the relat ive positions of peridinin molecules in the PCP complexes studied. The tetrameric arrangement of four peridinins around the chlorophyll a is suggested to favour the efficient transfer of energy from the peridin in to the chlorophyll. The simple arguments presented suggest that the energy transfer from peridin to chlorophyll might occur from the Psi( 1+/-) states of the peridinin tetramer to the B-x and B-y states of th e chlorophyll a.