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Peptide model helices in lipid membranes: insertion, positioning, and lipid response on aggregation studied by X-ray scattering

By Philipp E. Schneggenburger, André Beerlink, Britta Weinhausen, Tim Salditt and Ulf Diederichsen

Abstract

Studying membrane active peptides or protein fragments within the lipid bilayer environment is particularly challenging in the case of synthetically modified, labeled, artificial, or recently discovered native structures. For such samples the localization and orientation of the molecular species or probe within the lipid bilayer environment is the focus of research prior to an evaluation of their dynamic or mechanistic behavior. X-ray scattering is a powerful method to study peptide/lipid interactions in the fluid, fully hydrated state of a lipid bilayer. For one, the lipid response can be revealed by observing membrane thickening and thinning as well as packing in the membrane plane; at the same time, the distinct positions of peptide moieties within lipid membranes can be elucidated at resolutions of up to several angstroms by applying heavy-atom labeling techniques. In this study, we describe a generally applicable X-ray scattering approach that provides robust and quantitative information about peptide insertion and localization as well as peptide/lipid interaction within highly oriented, hydrated multilamellar membrane stacks. To this end, we have studied an artificial, designed β-helical peptide motif in its homodimeric and hairpin variants adopting different states of oligomerization. These peptide lipid complexes were analyzed by grazing incidence diffraction (GID) to monitor changes in the lateral lipid packing and ordering. In addition, we have applied anomalous reflectivity using synchrotron radiation as well as in-house X-ray reflectivity in combination with iodine-labeling in order to determine the electron density distribution ρ(z) along the membrane normal (z axis), and thereby reveal the hydrophobic mismatch situation as well as the position of certain amino acid side chains within the lipid bilayer. In the case of multiple labeling, the latter technique is not only applicable to demonstrate the peptide’s reconstitution but also to generate evidence about the relative peptide orientation with respect to the lipid bilayer

Topics: Original Paper
Publisher: Springer-Verlag
OAI identifier: oai:pubmedcentral.nih.gov:3070074
Provided by: PubMed Central

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Citations

  1. (2009). A novel heavy-atom label for side-specific peptide iodination: synthesis, membrane incorporation and X-ray reflectivity. Chem Phys Chem 10:1567–1576 Schneggenburger PE, Mu ¨llar
  2. (2000). Acta 1376:267–296 Mouritsen OG, Zuckermann MJ (2004) What’s so special about cholesterol?
  3. (1988). Acyl chain orientational order in the hexagonal HII phase of phospholipid-water dispersions.
  4. (2007). Chattopadhyay A
  5. (2007). Conformation and interaction of a D,Lalternating peptide with a bilayer membrane: X-ray reflectivity, CD, and FTIR spectroscopy. Chem Phys Chem 8:2336–2343 Lafleur
  6. (1985). Effects of the replacement of a double bond by a cyclopropane ring in phosphatidylethanolamines: a 2H-NMR study of the phase transition and molecular organization.
  7. (2001). Helix-helix packing and interfacial pairwise interaction of residues in membrane proteins.
  8. (2000). Membrane partitioning of the cleavage peptide in Flock House virus.
  9. (2002). Modulation of concentration fluctuations in phaseseparated lipid membranes by polypeptide insertion.
  10. (2009). Nichtlamellare Strukturen in Lipidmembranstapeln in Abha ¨ngigkeit der Hydratisation: Probenumgebung, Phasendiagramme und Bestimmung der Elektronendichte. Diploma Thesis, Georg-August-Universita ¨tG o ¨ttingen, Go ¨ttingen
  11. (1996). Peptide models for membrane channels.
  12. (2011). Salditt T (2006b) SARS coronavirus E protein in phospholipid bilayers: a X-ray scattering study.
  13. (1992). Structure of the molecular complex.
  14. (1986). Vibrational analysis of the structure of gramicidin A—I. Normal mode analysis. Biophys J 49:1131– Naik VM, Krimm S (1986b) Vibrational analysis of the structure of gramicidin A—II. Vibrational spectra. Biophys J 49:1147–1154 Oldfield E, Chapman D
  15. (1993). X-ray scattering with momentum transfer in the plane of membrane—application to gramicidin organization.