Low temperature absorption, fluorescence, and hole-burning spectroscopy ofphotosystem II reaction center complex containing 1 and 2 caroitenoides

Well defined photosystem II reaction centers from Pisum sativum containing 5 or 6 chlorophyll a (Chl a), 2 pheophytine a (Pheo a), and 1 or 2 beta-car otene (beta Car) molecules were prepared by using immobilized metal affinit y chromatography. Samples containing 6 Chl a and 1 or 2 beta-Car and contai ning 5 Chl a and 1 beta-Car were measured using low temperature absorption, fluorescence and hole-burning spectroscopy. Absorption bands of the beta Car (462, 490, and 508 nm) can be clearly dist inguished next to the Soret absorption band of Chl a at low temperature. Th eir relative intensities strongly depend on Chl/Car ratio. The shapes of fl uorescence bands are the same for all samples. Persistent spectral holes were burnt into both absorption, and fluorescence spectra. This technique provides lifetime of excited state tau(1) and Huan g-Rhys factor S. Values of tau(1) correspond to two picoseconds energy tran sfer in reaction centers. Huang-Rhys factor S = 0.4 appears to be the same for all studied samples. (C) 1999 Elsevier Science B.V. All rights reserved .