Both animals and plants possess potent, broad-spectrum antimicrobial peptides. Peptide antibiotics are ubiquitous components of host-defense system in various lives. The antimicrobial peptides in multicellular organisms offend the membranes of microbes selectively but for their cells, which provides insights to create new classes of anti-infective therapeutics. Extensive evidence showed that these small proteins or peptides (20–40 residues in length) act by permeabilizing the cell membranes of microorganisms.

Cell membranes consist of phospholipid bilayers, which play important roles in cells as matrices to support membrane proteins and as barriers for maintaining concentrations. The incorporation of peptides or proteins in cell membranes has been an important issue due to relevance of host-defense mechanism of multicellular organisms. Their physical properties have been widely investigated, showing the importance of membrane dynamics to the insertion of proteins and direct transport of small molecules. Interactions of amphiphilic helical peptides with phospholipid bilayers provide an interesting example of membrane-peptide interactions that can be understood in terms of the physical properties of the lipid layers.

Here, in order to address the interesting questions - how peptides interact with bio-membranes? We investigate the dynamics and structures of peptide/membrane systems using small angle neutron scattering and neutron spin echo techniques.