Article

BioNanoScience

, Volume 2, Issue 2, pp 108-112

First online:

Second Harmonic Generation to Monitor the Interactions of the Antimicrobial Mycosubtilin with Membrane-Mimicking Interfacial Monolayers

  • Mehmet Nail NasirAffiliated withInstitut de Chimie et Biochimie Moléculaires et Supramoléculaires, UMR CNRS 5246, Université Lyon 1 Email author 
  • , Emmanuel BenichouAffiliated withLaboratoire de Spectrométrie Ionique et Moléculaire, UMR CNRS 5579, Université Lyon 1
  • , Jean Sébastien GuezAffiliated withLaboratoire de Procédés Biologiques, Génie Enzymatique et Microbien (ProBioGEM, UPRES EA 1026), Polytech’Lille, IUT A, Université Lille Nord de France, USTL
  • , Philippe JacquesAffiliated withLaboratoire de Procédés Biologiques, Génie Enzymatique et Microbien (ProBioGEM, UPRES EA 1026), Polytech’Lille, IUT A, Université Lille Nord de France, USTL
  • , Pierre-François BrevetAffiliated withLaboratoire de Spectrométrie Ionique et Moléculaire, UMR CNRS 5579, Université Lyon 1
  • , Françoise BessonAffiliated withInstitut de Chimie et Biochimie Moléculaires et Supramoléculaires, UMR CNRS 5246, Université Lyon 1

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Abstract

Mycosubtilin is a strong antimicrobial agent belonging to the iturinic lipopeptide family which contains a single tyrosine residue. Its cell target has been shown to be the cytoplasmic membrane. This tyrosine residue has been previously shown to be essential for the biological activity of mycosubtilin. Since we have previously demonstrated that tyrosine, an aromatic amino acid, can be used as an endogenous probe for the frequency doubling process, the presence of a tyrosine residue in mycosubtilin allowed us to investigate the interactions of mycosubtilin with biomimetic lipid monolayers at the air–water interface by second harmonic generation (SHG). Mycosubtilin was added underneath dipalmitoylphosphatidylcholine or cholesterol monolayers at the air–water interface and significant increases in the surface pressure were observed in both cases. This observation demonstrates that mycosubtilin interacts with these biomimetic membranes. A light polarization resolved analysis of the SHG signals recovered for these two systems was then performed and confirmed that those interactions between the tyrosine residue in mycosubtilin and the membranes could be monitored by SHG. Furthermore, the differences exhibited by the nonlinear optical measurements for different membranes showed that these interactions depend on the nature of the biomimetic membrane present at the air–water interface.

Keywords

Mycosubtilin Biomimetic membranes Second harmonic generation Iturin Antimicrobial peptide