Excitation Energy Transfer: Functional and Dynamic Aspects of Lhc (cab) Proteins

Photosynthetic light-harvesting complexes have been the subject of extensive research because of interest in their primary function, namely the absorption of light and the transfer of excitation energy to a photochemical reaction center. As a result, a great deal of information has accumulated on the pigment co-factors, structure and folding of the corresponding proteins, molecular and supramolecular organization in the thylakoid membrane, and on their association with the photosystems. In addition to the structural-functional and assembly characteristics, this chapter reviews dynamic aspects of the light-harvesting complexes including the modulation of the light-harvesting antenna size by irradiance, the role of light-harvesting complexes in the regulation of excitation energy distribution between the two photosystems and the role they play as signal receptors for photosystem ratio adjustment in chloroplasts. Finally, the chapter examines aspects of exciton interactions between carotenoids and chlorophylls in the Lhc proteins and presents highlights of excitation transfer dynamics in the pigment bed of light-harvesting complexes.