Fig. 5.

Natamycin increases the accessibility to dithionite in a sterol-specific manner.

LUVs were prepared containing POPC, POPC/cholesterol or POPC/ergosterol (molar ratio 4:1), and POPC/SSM/ cholesterol or POPC/SSM/ ergosterol (molar ratio 4:1:1) without and with natamycin (molar ratio lipid/natamycin = 10). The reduction of NBD-PC's fluorescence upon the addition of dithionite was measured in POPC/ergosterol LUVs in the absence (black line) and in the presence (blue line) of natamycin as described in Materials and methods (A). This reveals a biphasic kinetics being characteristic for two differently accessible pools of NBD-PC. From the reduction curves, the rate constants (k_P) of dithionite access to the second pool were determined (B). The values with natamycin were normalized to those without natamycin. The mean values +/- SE are shown (1–2 independent samples each measured in triplicate).