Low-temperature absorption off-resonant hole-burning spectroscopy of pheophytine alpha in photosystem II reaction center

Chlorophylls, pheophytines and carotenes are main photosynthetic pigments. They play a crucial role in primary photosynthetic processes (excited energ y transfer and electron transport). In this contribution we report on both resonant and off-resonant hole-burning low-temperature absorption spectra. The resonant narrow zero-phonon holes together with broad (approximate to 8 4 cm(-1)) off-resonant holes were burnt into Q(y) absorption bands, while v ery broad (approximate to 250 cm(-1)) off-resonant satellite holes were obs erved in Q(x) absorption transitions. This technique enabled one to disting uish between satellite holes of chlorophyll a and pheophytine a and consequ ently to localize spectral bands of both pheophytines a in the complex Q(y) absorption spectrum of reaction center of photosystem II containing six ch lorophylls a, two pheophytines a and one beta-carotene. (C) 2000 Elsevier S cience B.V. All rights reserved.