BIOSAMP · Mechanism of interaction of antimicrobial peptides with the cell membrane - a study using bio-sensing technologies
FP6 — Marie Curie Actions (Human Resources and Mobility)
- Duration
- 2005-07-01 → 2006-06-30
- EU contribution
- €40,000
- Participants
- 1
- Scheme
- ERG
Lines connect the coordinator with its partners.
Results in brief
Final Activity Report Summary - BIOSAMP (Mechanism of interaction of antimicrobial peptides with the cell membrane - a study using bio-sensing technologies)
The goal of this work was to use a combination of novel and standard biosensing technologies to elucidate the molecular mechanisms that facilitate AMP interaction with microbial target cell membranes without lysing the host cell. Our approach in studying antimicrobial peptide/membrane interactions was to form simple membrane models that would retain the physiologically relevant membrane-fluidity but would luck other features that would complicate our study. Specifically, work performed was focused on the detection of the mechanism of interaction of alpha-defensins, a class of antimicrobial peptides, with model membranes. Biosensors based mainly on acoustic but also on optical transducers were applied for the real time detection of the peptide/membrane interaction. Model membranes were formed on the surface of the biosensor device by using the vesicle-fusion technique. Various combinations of surfaces and vesicles were tested in order to establish the optimum conditions for the bilayer formation. The effect of the membrane nature was assessed by forming supported lipid bilayers of various chemical compositions and/or surface charges; in addition, E.coli supported bilayers were formed based on E.coli lipids extract. The effect of the membrane charge was clearly shown in the alpha-defensin binding; increase of the membrane-charge increased the amount of peptide binding, indicating a strong electrostatic interaction between the two. In addition, it was shown that in all case, binding did not result in any type of major membrane disruption (including solubilisation), as indicated by both biosensing and fluorescent measurements. In general, real time acoustic data was proven a valuable technique for monitoring membrane interactions and distinguishing between pore formation (for example, during melittin binding) and membrane surface-binding events.
Data: CORDIS, © European Union
Project objective
Bacterial resistance to antibiotics threatens global health. Because bacteria have not developed resistance to naturally existing antimicrobial peptides (AMPs), AMPs or their derivatives offer promise as microbicidal agents. AMPs kill microbial cell but rarely damage the mammalian cells that produce and secrete them. Both mechanisms of interaction are poorly understood.This project will combine novel and standard bio-sensing technologies with alpha-defensins (a-Defs) with varying potencies and distinct mechanisms of membrane disruption in order to test hypotheses directed at the molecular mechanisms of a-Def action. Fully characterised recombinant mammalian a-Defs and a-Defs with site-directed mutations will be used with model membranes that mimic bacterial and mammalian membrane systems. These model membranes, supported on the surface of two biosensors will be used to study the mechanism of interaction of the above AMPs with the membranes.Optical biosensors based on Surface Plasmon Resonance (SPR) and novel acoustic wave devices based on shear horizontal surface acoustic waves (SH-SAW) will be used to monitor changes in the mass and elasticity of the model supported lipid bilayers during peptide binding. Real time data will be used to derive quantitative information on the binding and kinetic constants of the peptide-membrane. Comparison between optical and acoustic wave data will be used to distinguish between peptide surface binding from bilayer insertion.We hypothesize that the combination of the above re al time techniques will provide insights into why these endogenous membrane-active molecules do not kill their cells of origin. Proof of these principles is directly applicable to future development of new therapeutic pathways for infectious diseases. In addition the successful application of the above two biosensors will open new possibilities in biophysical analysis and will introduce opto-acoustic measurements as a novel powerful bio-analytical tool.
Original text from CORDIS.
Participants
- FOUNDATION OF RESEARCH AND TECHNOLOGY - HELLAS · IRAKLIONCoordinatorGreece
Links
Data: CORDIS, © European Union