Insights on the interaction of met-enkephalin with negatively charged membranes--an infrared and solid-state NMR spectroscopic study.
Enkephalins are pentapeptides found in the human nervous system, where they are involved in the relief of pain. The interaction of these neuropeptides with the nerve cell membranes would be a key-step in the receptor binding. We have used both Fourier-transform infrared and solid-state NMR spectroscopies to shed light on the interactions responsible for the association of enkephalins with negatively charged membranes. More specifically, we have investigated the interaction of methionine-enkephalin (Menk) with DMPG and DMPS vesicles. Our results suggest that Menk interacts electrostatically with both model membranes via its terminal NH3+ group. However, the peptide induced the formation of elongated DMPG vesicles in the magnetic field. On the other hand, the association of Menk with DMPS bilayers was concentration-dependent and disrupted the membrane at high peptide concentrations. The different effect of methionine-enkephalin with the two types of anionic membranes is most likely related to the different fluidity of these systems.
Marcotte
Isabelle
I
Département de Chimie, Centre de Recherche en Sciences et Ingénierie des Macromolécules (CERSIM), Université Laval, Québec, Qué., Canada G1K 7P4.
Ouellet
Marise
M
Auger
Michèle
M
D000838:Anions; D003903:Deuterium; D004574:Electromagnetic Fields; D004744:Enkephalin, Methionine / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008560:Membrane Fluidity; D008565:Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D008823:Micelles; D010715:Phosphatidylglycerols / Q000737:chemistry; D010759:Phosphorus Isotopes; D011485:Protein Binding; D055672:Static Electricity; D013696:Temperature; D014494:Unithiol / Q000737:chemistry
D000838:Anions; D008051:Lipid Bilayers; D008565:Membrane Proteins; D008823:Micelles; D010715:Phosphatidylglycerols; D010759:Phosphorus Isotopes; D014494:Unithiol; D004744:Enkephalin, Methionine; D003903:Deuterium; C002773:dimyristoylphosphatidylglycerol