Membrane perturbation induced by interfacially adsorbed peptides

Assaf Zemel, Avinoam Ben-Shaul, Sylvio May*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

The structural and energetic characteristics of the interaction between interfacially adsorbed (partially inserted) α-helical, amphipathic peptides and the lipid bilayer substrate are studied using a molecular level theory of lipid chain packing in membranes. The peptides are modeled as "amphipathic cylinders" characterized by a well-defined polar angle. Assuming two-dimensional nematic order of the adsorbed peptides, the membrane perturbation free energy is evaluated using a cell-like model; the peptide axes are parallel to the membrane plane. The elastic and interfacial contributions to the perturbation free energy of the "peptide-dressed" membrane are evaluated as a function of: the peptide penetration depth into the bilayer's hydrophobic core, the membrane thickness, the polar angle, and the lipid/peptide ratio. The structural properties calculated include the shape and extent of the distorted (stretched and bent) lipid chains surrounding the adsorbed peptide, and their orientational (C-H) bond order parameter profiles. The changes in bond order parameters attendant upon peptide adsorption are in good agreement with magnetic resonance measurements. Also consistent with experiment, our model predicts that peptide adsorption results in membrane thinning. Our calculations reveal pronounced, membrane-mediated, attractive interactions between the adsorbed peptides, suggesting a possible mechanism for lateral aggregation of membrane-bound peptides. As a special case of interest, we have also investigated completely hydrophobic peptides, for which we find a strong energetic preference for the transmembrane (inserted) orientation over the horizontal (adsorbed) orientation.

Original languageAmerican English
Pages (from-to)3607-3619
Number of pages13
JournalBiophysical Journal
Volume86
Issue number6
DOIs
StatePublished - Jun 2004

Bibliographical note

Funding Information:
We thank Dr. Klaus Gawrisch for fruitful discussions. S.M. thanks the Thüringer Ministerium für Wissenschaft, Forschung und Kunst. A. Z. thanks the Yeshaya Horowitz Foundation for a doctoral fellowship.

Funding Information:
The financial support of the Israel Science Foundation and the United States-Israel Binational Science Foundation is gratefully acknowledged. The Fritz Haber Center is supported by the Minerva Foundation, Munich, Germany.

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