Energy Transfer between Surface-immobilized Light-Harvesting Chlorophyll a/b Complex (LHCH) Studied by Surface Plasmon Field-Enhanced Fluorescence Spectroscopy (SPFS)

The major light-harvesting chlorophyll a/b complex (LHCH) of the photosynthetic apparatus in green plants can be viewed as a protein scaffold binding and positioning a large number of pigment molecules that combines rapid and efficient excitation energy transfer with effective protection of its pigments from photobleaching. These properties make LHCH potentially interesting as a light harvester (or a model thereof) in photoelectronic applications. Most of such applications would require the LHCH to be immobilized on a solid surface. In a previous study we showed the immobilization or recombimint LHCH on functionalized gold surfaces via it 6-histicline tag (His tag) in the protein moiety. In this work the occurrence and efficiency of Forster energy transfer between immobilized LHCH on a functionalized surface have been analyzed by surface plasmon held-enhanced fluorescence spectroscopy (SPFS). A near-infrared dye was attached to some but not all of the LHC complexes, serving as an energy acceptor to chlorophylls. Analysis of the energy transfer from chlorophylls to this acceptor dye yielded information about the extent of intercomplex energy transfer between immobilized LHCH.