title: A thermodynamic signature of lipid segregation in biomembranes induced by a short peptide derived from glycoprotein gp36 of feline immunodeficiency virus.
abstract: The interactions between proteins/peptides and lipid bilayers are fundamental in a variety of key biological processes, and among these, the membrane fusion process operated by viral glycoproteins is one of the most important, being a fundamental step of the infectious event. In the case of the feline immunodeficiency virus (FIV), a small region of the membrane proximal external region (MPER) of the glycoprotein gp36 has been demonstrated to be necessary for the infection to occur, being able to destabilize the membranes to be fused. In this study, we report a physicochemical characterization of the interaction process between an eight-residue peptide, named C8, modeled on that gp36 region and some biological membrane models (liposomes) by using calorimetric and spectroscopic measurements. CD studies have shown that the peptide conformation changes upon binding to the liposomes. Interestingly, the peptide folds from a disordered structure (in the absence of liposomes) to a more ordered structure with a low but significant helix content. Isothermal titration calorimetry (ITC) and differential scanning calorimetry (DSC) results show that C8 binds with high affinity the lipid bilayers and induces a significant perturbation/reorganization of the lipid membrane structure. The type and the extent of such membrane reorganization depend on the membrane composition. These findings provide interesting insights into the role of this short peptide fragment in the mechanism of virus-cell fusion, demonstrating its ability to induce lipid segregation in biomembranes.
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy.
authors.forename: Rosario
authors.initials: R
authors.lastname: Oliva
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy.
authors.forename: Pompea
authors.initials: P
authors.lastname: Del Vecchio
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy.
authors.forename: Marco Ignazio
authors.initials: MI
authors.lastname: Stellato
authors.affiliation: Department of Pharmaceutical Science, University of Salerno, Fisciano, Italy.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: D'Ursi
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy.
authors.forename: Gerardino
authors.initials: G
authors.lastname: D'Errico
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Paduano
authors.affiliation: Department of Chemical Sciences, University of Naples "Federico II", Naples, Italy. Electronic address: luigi.petraccone@unina.it.
authors.forename: Luigi
authors.initials: L
authors.lastname: Petraccone
mesh_terms: D002784:Cholesterol / Q000737:chemistry; D002942:Circular Dichroism; D016089:Immunodeficiency Virus, Feline / Q000737:chemistry; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry*; D010713:Phosphatidylcholines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013109:Sphingomyelins / Q000737:chemistry; D013816:Thermodynamics; D014760:Viral Fusion Proteins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D008081:Liposomes; D010455:Peptides; D010713:Phosphatidylcholines; D010715:Phosphatidylglycerols; D013109:Sphingomyelins; D014760:Viral Fusion Proteins; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; D002784:Cholesterol; C028694:1-palmitoyl-2-oleoylphosphatidylcholine
keywords: Differential scanning calorimetry; Isothermal titration calorimetry; Lipid domain formation; Lipid–peptide interaction; Model membranes; Thermodynamics