Open AccessThe Detection of Ionophorous Antibiotic-Cation Complexes in Water with Fluorescent Probes
Author(s) -
Maurice B. Feinstein,
Herbert Felsenfeld
Publication year - 1971
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.68.9.2037
Subject(s) - nigericin , valinomycin , fluorescence , chemistry , alamethicin , gramicidin , ionophore , fluorophore , aqueous solution , sulfonate , photochemistry , inorganic chemistry , potassium , membrane , sodium , lipid bilayer , organic chemistry , biochemistry , physics , quantum mechanics
The binding of alkali cations by the ionophorous antibiotics valinomycin, nigericin, alamethicin, and the macrotetralide actins has been shown to occur, in aqueous media, by the use of the fluorescent probes 1-anilino-8-naphthalene sulfonate and 2-p-toluidinyl-6-naphthalene sulfonate. The interaction of the ionophore-cation complexes with the fluorescent dyes produced enhanced fluorescence emission, increased lifetime and polarization, and a significant blue-shift of the emission maxima of the fluorescence spectrum. At constant antibiotic and fluorophore concentrations in water, the intensity of the fluorescence emission was found to be a function of the cation concentration. This permitted relative cation affinities to be determined for alamethicin (Na(+) congruent with K(+)), valinomycin (Rb(+) > K(+) > Cs(+)), nigericin (K(+) > Rb(+) > Na(+) > Cs(+)) and trinactin (NH(4) (+) > K(+) > Rb(+) > Cs(+)).