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| {{STRUCTURE_1d7n| PDB=1d7n | SCENE= }} | | {{STRUCTURE_1d7n| PDB=1d7n | SCENE= }} |
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| '''SOLUTION STRUCTURE ANALYSIS OF THE MASTOPARAN WITH DETERGENTS'''
| | ===SOLUTION STRUCTURE ANALYSIS OF THE MASTOPARAN WITH DETERGENTS=== |
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| ==Overview==
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| 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.
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| | (as it appears on PubMed at http://www.pubmed.gov), where 11168364 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_11168364}} |
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| ==About this Structure== | | ==About this Structure== |
| 1D7N is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Vespula_lewisii Vespula lewisii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D7N OCA]. | | 1D7N is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Vespula_lewisii Vespula lewisii]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D7N OCA]. |
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| ==Reference== | | ==Reference== |
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| [[Category: Immune system]] | | [[Category: Immune system]] |
| [[Category: Sodium dodecyl sulfate bound conformation]] | | [[Category: Sodium dodecyl sulfate bound conformation]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 13:32:17 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jun 30 22:37:58 2008'' |
