Figure 4.
Thermal denaturation studies of the model antimicrobial peptide (KIGAKI)3. (a) The wild-type peptide forms β-pleated aggregates in DMPC/DMPG 3:1 liposomes (P/L 1:50), as can be deduced from the characteristic spectral line shape of the SRCD spectra. Upon heating up to 353 K, only a slight and reversible decrease in β-sheet fraction is observed. (b) For a mutant peptide, in which Ile-8 was replaced by a rigid fluorinated d-amino acid, extensive and irreversible unfolding of the β-pleated aggregates is observed, and even the formation of small helical fractions can be stated for the same heating/cooling cycle.