BODIPY-labeled ganglioside probes for membrane and biological studies

A series of new fluorescent ganglioside G_M1 derivatives bearing the residue of 4,4-difluoro-4-bora-3a,4a-diaza-s-indecene (BODIPY) either in the polar or nonpolar part of the molecule have been synthesized. Gangliosides G_M1 labeled with the residues of (4,4-difluoro-5-styryl-4-bora-3a,4a-diaza-s-indecenyl)-5-pentanoic (564/570-BODIPY-pentanoic) acid and (4,4-difluoro-5-butadienylphenyl-4-bora-3a,4a-diaza-s-indecenyl)-11-undecanoic (581/591-BODIPY-undecanoic) acid at the nonpolar part of the molecule or with the residue of (4,4-difluoro-5-butadienylphenyl-4-bora-3a,4a-diaza-s-indecenyl)-5-pentanoic (581/591-BODIPY-pentaoic) acid at the polar part of the molecule have been synthesized. The spectral characteristics of the resulting probes and their behavior in ganglioside G_M1 micelles and in sphingomyelin-cholesterol enriched bilayers containing BODIPY-FL-labeled gangliosides G_M1 have been studied. The localization of the label in the ganglioside molecule has been demonstrated to affect the efficiency of energy transfer in the case of the corresponding donor-acceptor pairs.