Action of Arginine and Tryptophan Containing Antimicrobial Peptides on Supported Lipid Bilayers

Direct observation and quantitative insights of the dynamics of interactions between membranes and antimicrobial peptides greatly aid in understanding the mechanisms by which their exert their action. We previously developed a correlated total-internal reflectance fluorescence-atomic force microscopy (TIRF-AFM) platform that enabled direct determination of local order within the membrane [Oreopoulos and Yip, 2009]. We report here, the results of combinatorial studies using this platform into the activity of arginine and tryptophan containing antimicrobial peptides on supported lipid bilayers of varying compositions. These studies provide direct evidence of membrane destruction and insight into the mechanisms by which they act. These studies portend to the usefulness of other correlated approaches, such as coupled ATR-IR-AFM, to directly observe and quantify interactions between membranes and membrane active molecules.