This project will examine the dynamics of energy excitation, migration and trapping reactions in the Photosystem I core and peripheral antenna complexes of algae and higher plants. The spectral and temporal properties of excitation decay will be measured using several picosecond-resolved spectroscopic techniques. Biochemical and genetic manipulations of the photosystem apparatus will be used to simplify and dissect the Photosystem I antennae. The photosynthetic conversion of light energy into biologically useful compounds in bacteria, algae and higher plants provides the ultimate energy source for much of life on earth. The initial steps of photosynthesis are in the photophysical and photochemical domains and are localized in several types of pigment-protein complexes that function either as reaction center or light-harvesting antenna complexes. The complex antenna system efficiently absorbs and transfers light energy to the reaction centers. The reaction centers are the site of the photochemical energy transduction. The reaction center and its energetically coupled antenna pigments are the functional definition of the photosynthetic unit.
