Emission spectra (arbitrary units, A.U.) of USP AmB (i), generic AmB (ii), AmBHP (iii) and AmBHP in the presence of nystatin (iv). Each AmB preparation was dissolved in DMSO to a final concentration of ∼10 µM; nystatin was added to a final concentration of 0.5 µM. (a) 408 nm excitation, (b) 350 nm excitation, (c) 335 nm excitation and (d) 325 nm excitation. Since spectra in (a) are not distinguishable, they are not individually labelled. This figure appears in colour in the online version of JAC and in black and white in the print version of JAC.