Orientational behavior of phospholipid membranes with mastoparan studied by P-31 solid state NMR

Solid state P-31 NMR spectroscopy was used to study the perturbing effect o f the wasp venom peptide mastoparan (MP) on lipid bilayers composed of dimy ristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylglycerol (DMPG ). The P-31 chemical shift anisotropy of multilamellar vesicles decreased w ith increasing peptide concentration, indicating that MP interacts strongly and selectively with the charged DMPG head group, Macroscopically oriented MP-lipid samples between glass plates were studied by P-31 NMR as a functi on of tilt angle. These spectra showed the coexistence of orientation-depen dent lamellar signals as well as an isotropic peak, suggesting that MP can induce non-lamellar phases in DMPC/DMPG membranes. (C) 1999 Federation of E uropean Biochemical Societies.