Lipid Membrane-Binding Properties of Daptomycin Using Surface Plasmon Resonance

In the present study, we developed an assay of interactions of daptomycin with four model lipid membranes that mimicked mammal cell membranes and gram-positive and negative bacteria membranes. We also analyzed the binding kinetics of the gram-positive bacteria membranes using surface plasmon resonance (SPR). Daptomycin showed a higher affinity for the model gram-positive bacteria membrane than those of the model mammal cell and gram-negative bacteria membranes, and the binding selectivity of daptomycin in the presence of calcium could be represented by this SPR system. This method also showed reproducible immobilization of model liposome membranes on the sensor chip, and had a desirable repeatability in the analysis of the binding kinetics to the model gram-positive bacteria membranes. The results demonstrate that this newly established SPR method could be a valuable tool for predicting the binding characteristics of antimicrobial agents to lipid membranes.