Fluorescence of pyrene in galactolipid liposomes and native membranes of etioplasts

The fluorescence parameters of pyrene and pyrenedecanoic acid in lipid micelles and native membranes of etioplasts whose basic lipid components are mono- and digalactosyldiacylglycerol (MGDG and DGDG) have been investigated. The vibrational structure of the emission spectra of pyrene (λ_exc = 337 nm) in the 370–400-nm range points to the hydrophilic microsurrounding of pyrene molecules in all types of the investigated membranes. The absence of MGDG from liposomes leads to a decrease in the degree of excimerization of a probe. In native membranes, this parameter increases with increasing content of pigments. Pyrene covalently bound to decanoic acid is found in the membranes of prolamellar bodies and in artificial monolayer micellae in an even more hydrophilic microsurrounding than the molecules of a free probe, and a decrease in the degree of eximerization is observed thereby. The specific features of localization of the investigated probes in plastid membranes are discussed. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 344–349, May–June, 2000.