PDBsum entry 1d7n

Toxin

PDB id: 1d7n

Contents

Protein chain

15 a.a.

PDB id:

1d7n

Name:

Toxin

Title:

Solution structure analysis of the mastoparan with detergents

Structure:

Protein (wasp venom peptide (mastoparan)). Chain: a

Source:

Vespula lewisii. Organism_taxid: 7452. Secretion: venom

NMR struc:

10 models

Authors:

Y.Hori,M.Demura,M.Iwadate,T.Niidome,H.Aoyagi,T.Asakura

Key ref:

Y.Hori et al. (2001). 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. Eur J Biochem, 268, 302-309. PubMed id: 11168364 DOI: 10.1046/j.1432-1033.2001.01880.x

Date:

19-Oct-99 Release date: 20-Jun-01

Protein chain

P01514  (MAST_VESLE) -  Mastoparan-L from Vespula lewisii

Seq: 14 a.a.

Struc: 15 a.a.

DOI no: 10.1046/j.1432-1033.2001.01880.x

Eur J Biochem 268:302-309 (2001)

PubMed id: 11168364

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.

Y.Hori, M.Demura, M.Iwadate, A.S.Ulrich, T.Niidome, H.Aoyagi, T.Asakura.

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 alpha-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 alpha-segments and beta-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 degrees and +/- 10 degrees, 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.

Selected figure(s)

Figure 3.
Fig. 3. ^2H-NMR spectra of DMPC-d[4] in uniaxially oriented bilayers. Pure DMPC-d[4] (A), DMPC-d[4]/DMPG (70 : 30) (B), DMPC-d[4]/DMPG/mastoparan (70 : 30 : 10) (C) at 35 °C. Each sample was oriented between glass plates and aligned with its normal parallel to the static magnetic field direction.

Figure 4.
Fig. 4. Experiments to discriminate between the electrostatic and dynamic effects of mastoparan binding to DMPC and DMPC/DMPG bilayers. (A) Narrowing of the ^31P CSA (left scale, full lines) of DMPC and DMPC/DMPG bilayers induced by the addition of mastoparan. The ^2H-NMR quadrupole splittings (right scale, dashed line) of headgroup deuterated DMPC-d[4] are reduced to the same extent ( and remain equivalent), hence the choline and phosphate groups respond by a similar increase in motional averaging. (B) When negatively charged DMPG was added, the and quadrupole splittings of headgroup-deuterated DMPC-d[4] changed linearly and in a counter-directional manner.

The above figures are reprinted by permission from the Federation of European Biochemical Societies: Eur J Biochem (2001, 268, 302-309) copyright 2001.

Figures were selected by an automated process.