Optical absorption of Chlorophylls in LH-II complex of spinach

EDGAR ALEJANDRO BEA; XAVIER ANDRADE; ALEJANDRO SOBA; ANGEL RUBIO

Villa Carlos Paz

Congreso; XLII Reunión Anual de la Sociedad Argentina de Biofísica; 2013

Universidad Nacional de Córdoba

The light harvesting (LH) is the primary process in photosynthesis. In green plants, this function is developed by a series of pigment-protein complexes in thylakoid membrane of chloroplasts. The LH-II complex is the most abundant and is involved in regulating and channeling of excitation energy to reaction centres, with photochemical activity. It is known that the excitation moves through intricate networks of pigments which constitute the complex "antenna". Chlorophylls are the main pigments and are associated with proteins and other pigments. Chlorophyll a is involved in the photochemical activity of the active site, where it becomes radiant energy (light) into chemical energy when it receives a photon from the antenna. The dynamics of energy transfer is highly efficient, thus it is attractive and motivating to know precise mechanisms involved. In this work, as a first approach in studying of spinach LHC-II, the excited state of a Chlorophyll a (in protein environment) is characterzed theoretically from electron system evolution by Ehrenfest TD-DFT dynamics. The Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional is used.