Antimicrobial peptides (AMPs) are naturally occurring molecules that can kill bacteria by destabilizing bacterial membranes and causing lysis.  However, the active mechanism behind the membrane destabilization is not well understood. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used to investigate the action of sheep myeloid antimicrobial peptide-29 (SMAP-29) on a supported lipid bilayer of phosphatidylcholine. The changes in frequency and dissipation of the film, which can be related to changes in mass and viscoelasticity, were measured as it was exposed to SMAP-29. Concentrations of SMAP-29 above 2 �M resulted in an increase in the membrane's mass, which was non-uniform throughout the bilayer, indicating both peptide adsorption on the bilayer surface and insertion into the membrane to form pores. By analyzing various AMP and lipid bilayer systems using QCM-D, we will be able to gain a more detailed understanding of how AMPs interact with bacterial cell membranes in future work.

Using QCM-D to deduce the mechanism of SMAP-29 action on a model membrane

243rd National Meeting (2012)

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