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Interaction of mastoparan with membranes studied by 1H‐NMR spectroscopy in detergent micelles and by solid‐state 2H‐NMR and 15N‐NMR spectroscopy in oriented lipid bilayers

Interaction of mastoparan with membranes studied by 1H‐NMR spectroscopy in detergent micelles and... Several complementary NMR approaches were used to study the interaction of mastoparan, a 14‐residue peptide toxin from wasp venom, with lipid membranes. First, the 3D structure of mastoparan was determined using 1H‐NMR spectroscopy in perdeuterated (SDS‐d25) micelles. NOESY experiments and distance geometry calculations yielded a straight amphiphilic α‐helix with high‐order parameters, and the chemical shifts of the amide protons showed a characteristic periodicity of 3–4 residues. Secondly, solid‐state 2H‐NMR spectoscopy was used to describe the binding of mastoparan to lipid bilayers, composed of headgroup‐deuterated dimyristoylglycerophosphocholine (DMPC‐d4) and dimyristoylphosphatidylglycerol (DMPG). By correlating the deuterium quadrupole splittings of the α‐segments and β‐segments, it was possible to differentiate the electrostatically induced structural response of the choline headgroup from dynamic effects induced by the peptide. A partial phase separation was observed, leading to a DMPG‐rich phase and a DMPG‐depleted phase, each containing some mastoparan. Finally, the insertion and orientation of a specifically 15N‐labeled mastoparan (at position Ala10) in the bilayer environment was investigated by solid‐state 15N‐NMR spectroscopy, using macroscopically oriented samples. Two distinct orientational states were observed for the mastoparan helix, namely an in‐plane and a trans‐membrane alignment. The two populations of 90% in‐plane and 10% trans‐membrane helices are characterized by a mosaic spread of ± 30° and ± 10°, respectively. The biological activity of mastoparan is discussed in terms of a pore‐forming model, as the peptide is known to be able to induce nonlamellar phases and facilitate a flip‐flop between the monolayers. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Febs Journal Wiley

Interaction of mastoparan with membranes studied by 1H‐NMR spectroscopy in detergent micelles and by solid‐state 2H‐NMR and 15N‐NMR spectroscopy in oriented lipid bilayers

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References (41)

Publisher
Wiley
Copyright
Copyright © 2001 Wiley Subscription Services, Inc., A Wiley Company
ISSN
1742-464X
eISSN
1742-4658
DOI
10.1046/j.1432-1033.2001.01880.x
Publisher site
See Article on Publisher Site

Abstract

Several complementary NMR approaches were used to study the interaction of mastoparan, a 14‐residue peptide toxin from wasp venom, with lipid membranes. First, the 3D structure of mastoparan was determined using 1H‐NMR spectroscopy in perdeuterated (SDS‐d25) micelles. NOESY experiments and distance geometry calculations yielded a straight amphiphilic α‐helix with high‐order parameters, and the chemical shifts of the amide protons showed a characteristic periodicity of 3–4 residues. Secondly, solid‐state 2H‐NMR spectoscopy was used to describe the binding of mastoparan to lipid bilayers, composed of headgroup‐deuterated dimyristoylglycerophosphocholine (DMPC‐d4) and dimyristoylphosphatidylglycerol (DMPG). By correlating the deuterium quadrupole splittings of the α‐segments and β‐segments, it was possible to differentiate the electrostatically induced structural response of the choline headgroup from dynamic effects induced by the peptide. A partial phase separation was observed, leading to a DMPG‐rich phase and a DMPG‐depleted phase, each containing some mastoparan. Finally, the insertion and orientation of a specifically 15N‐labeled mastoparan (at position Ala10) in the bilayer environment was investigated by solid‐state 15N‐NMR spectroscopy, using macroscopically oriented samples. Two distinct orientational states were observed for the mastoparan helix, namely an in‐plane and a trans‐membrane alignment. The two populations of 90% in‐plane and 10% trans‐membrane helices are characterized by a mosaic spread of ± 30° and ± 10°, respectively. The biological activity of mastoparan is discussed in terms of a pore‐forming model, as the peptide is known to be able to induce nonlamellar phases and facilitate a flip‐flop between the monolayers.

Journal

The Febs Journal – Wiley

Published: Jan 1, 2001

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