Calcium-Induced Formation of Subdomains in Phosphatidylethanolamine−Phosphatidylglycerol Bilayers: A Combined DSC, 31 P NMR, and AFM Study - Compartimentation et dynamique cellulaires Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry B Année : 2009

Calcium-Induced Formation of Subdomains in Phosphatidylethanolamine−Phosphatidylglycerol Bilayers: A Combined DSC, 31 P NMR, and AFM Study

Laura Picas
M Teresa Montero
  • Fonction : Auteur
Antoni Morros
  • Fonction : Auteur
Bastien Seantier
  • Fonction : Auteur
  • PersonId : 1019790
Jordi Hernández-Borrell
  • Fonction : Auteur
M. Teresa Montero
  • Fonction : Auteur
Miquel Cabañas
  • Fonction : Auteur
Jordi Hernández-Borrell
  • Fonction : Auteur

Résumé

We study the effect of Ca(2+) on the lateral segregation of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) (3:1, mol/mol). Supported lipid bilayers (SLBs) were observed by atomic force microscopy (AFM). Since SLBs are formed from liposomes of POPE:POPG, we examined the effect of calcium on these suspensions by differential scanning calorimetry (DSC) and (31)P nuclear magnetic resonance spectroscopy ((31)P NMR). AFM images revealed the existence of two separated phases, the higher showing a region with protruding subdomains. Force spectroscopy (FS) was applied to clarify the nature of each phase. The values of breakthrough force (F(y)), adhesion force (F(adh)), and height extracted from the force curves were assigned to the corresponding gel (L(beta)) and fluid (L(alpha)) phase. The endotherms obtained by DSC suggest that, in the presence of Ca(2+), phase separation already exists in the suspensions of POPE:POPG used to form SLBs. Due to the temperature changes applied during preparation of SLBs a (31)P NMR study was performed to assess the lamellar nature of the samples before spreading them onto mica. With in situ AFM experiments we showed that the binding of Ca(2+) to POPG-enriched domains only induces the formation of subdomains in the L(beta) phase.

Domaines

Biophysique
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Dates et versions

hal-02289079 , version 1 (16-09-2019)

Identifiants

Citer

Laura Picas, M Teresa Montero, Antoni Morros, Miquel E. Cabañas, Bastien Seantier, et al.. Calcium-Induced Formation of Subdomains in Phosphatidylethanolamine−Phosphatidylglycerol Bilayers: A Combined DSC, 31 P NMR, and AFM Study. Journal of Physical Chemistry B, 2009, 113 (14), pp.4648-4655. ⟨10.1021/jp8102468⟩. ⟨hal-02289079⟩
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