Surface plasmon resonance spectroscopy for studying the membrane binding of antimicrobial peptides

Surface plasmon resonance (SPR) employs the optical principle of SPR to measure changes in mass on a sensor chip surface in real time. Surface chemistry has been developed which enables the immobilization of lipid bilayers and determination of protein-membrane interactions in real time. Antimicrobial peptides are being increasingly recognized as potential candidate antibacterial drugs in the face of the rapidly emerging bacterial resistance to conventional antibiotics in recent years. However, a precise understanding of the relationship between antimicrobial peptide structure and their cytolytic function in a range of organisms is still lacking. This is a result of the complex nature of the interactions of antimicrobial peptides with the cell membrane, the mechanism of which can vary considerably between different classes of antimicrobial peptides. SPR has recently been applied to the study of biomembrane-based systems which has allowed a real-time analysis of binding affinity and kinetics. This chapter describes an SPR method to study the membrane interactions of melittin, a well-known antimicrobial peptide.