POSSIBLE NYSTATIN-PROTEIN INTERACTION IN YEAST PLASMA-MEMBRANE VESICLES IN THE PRESENCE OF ERGOSTEROL - A FORSTER ENERGY-TRANSFER STUDY

The Forster energy transfer from tryptophan residues of membrane prote ins to nystatin was measured in reconstituted yeast plasma membrane ve sicles free of, or doped with, ergosterol, We wanted to elucidate whet her the functional change of membrane transport proteins from H+ sympo rters to facilitators, observed in ergosterol-containing plasma membra ne vesicles on addition of nystatin [Opekarova and Tanner (1994) FEES Lett, 350, 46-50], is reflected in altered protein-nystatin relations within the membrane, Both frequency-domain and time-domain time-resolv ed fluorescence spectroscopy showed that in the presence of ergosterol nystatin is located much closer to membrane proteins than in its abse nce.