Lipid saturation and head group composition have a pronounced influence on the membrane insertion equilibrium of amphipathic helical polypeptides.
Fiche publication
Date publication
décembre 2021
Journal
Biochimica et biophysica acta. Biomembranes
Auteurs
Membres identifiés du Cancéropôle Est :
Pr BECHINGER Burkhard
Tous les auteurs :
Salnikov E, Aisenbrey C, Bechinger B
Lien Pubmed
Résumé
The histidine-rich peptides of the LAH4 family were designed using cationic antimicrobial peptides such as magainin and PGLa as templates. The LAH4 amphipathic helical sequences exhibit a multitude of interesting biological properties such as antimicrobial activity, cell penetration of a large variety of cargo and lentiviral transduction enhancement. The parent peptide associates with lipid bilayers where it changes from an orientation along the membrane interface into a transmembrane configuration in a pH-dependent manner. Here we show that LAH4 adopts a transmembrane configuration in fully saturated DMPC membranes already at pH 3.5, i.e. much below the pK of the histidines whereas the transition pH in POPC correlates closely with histidine neutralization. In contrast in POPG membranes the in-planar configuration is stabilized by about one pH unit. The differences in pH can be converted into energetic contributions for the in-plane to transmembrane transition equilibrium, where the shift in the transition pH due to lipid saturation corresponds to energies which are otherwise obtained by the exchange of several cationic with hydrophobic residues. A similar dependence on lipid saturation has also been observed when the PGLa and magainin antimicrobial peptides interact within lipid bilayers suggesting that the quantitative evaluation presented in this paper also applies to other membrane polypeptides.
Mots clés
Hydrophobic mismatch, Lipid order parameter, Lipophobic effect, Magainin, Molecular shape, PGLa, Solid-state NMR, Supported lipid bilayer, helix topology
Référence
Biochim Biophys Acta Biomembr. 2021 Dec 23;:183844