Specific and selective peptide-membrane interactions revealed using quartz crystal microbalance

Abstract

The skin secretions of Australian tree frogs are rich in peptides with potential antimicrobial activity. They interrupt bacterial cell membranes, although precisely how and whether all peptides have the same mechanism is not known. The interactions of three of these peptides - aurein 1.2, maculatin 1.1, and caerin 1.1 with supported phospholipid bilayers - are examined here using quartz crystal microbalance and atomic force microscopy. These approaches enabled us to reveal variations in material structure and density as a function of distance from the sensor surface when comparing mass sensorgrams over a range of harmonics of the natural resonance of the sensor crystal and hence obtain for t..