The major carotenoid pigment of a psychrotrophic Micrococcus roseus strain: fluorescence properties of the pigment and its binding to membranes.

The fluorescence excitation and emission spectra are reported for P-3 (bis-dehydro-B-carotene-2-carboxylic acid), the major carotenoid pigment of psychrotrophic M. roseus. The excitation spectrum and the absorption spectrum showed good agreement with respect to the position of their peak maxima. The study also demonstrates that P-3 binds to liposomes prepared from synthetic lipids (PC, DOPG, or CL) or the total lipids of a mutant colourless M. roseus. Binding of P-3 to the membranes was accompanied by a decrease in the fluorescence emission intensity and a blue shift in lambda(em) maximum by 15 to 20 nm. The quantum yield of P-3 was observed to be low (1.7 x 10(-5)).