title: Analysis of the effect of a peptide sequence of the E2 protein (HGV/GBV-C) on the physicochemical properties of zwitterionic and negatively charged bilayers.
abstract: The membrane-interacting properties of a potential epitope of GB virus C/hepatitis G virus located at the region (99-118) of the E2 structural protein were investigated using several fluorescence techniques. SUV of DMPC:DPPC (1:1) or DMPG:DPPC (1:1) zwitterionic and anionic mixtures, respectively, were used as model membranes. FRET with NBD-PE as energy donor and Rho-PE as energy acceptor-labelled SUV indicated that the peptide was able to fuse both zwitterionic and anionic SUVs, the latter requiring lower peptide concentrations. However, the peptide increased the steady-state anisotropy of DPH embedded in the hydrophobic centre of the membrane with zwitterionic headgroups and to a lesser extent in anionic bilayers, suggesting that charge-charge interactions are not required for membrane interactions and also confirming the FRET results. No changes in anisotropy were observed with the probe TMA-DPH located at the surface of the bilayer. Finally, analysis of the intrinsic emission fluorescence of the tryptophan residue, upon incubation with SUV, showed a blue shift in the presence of anionic bilayers, both below and above the main transition temperature (T(m)) (gel to liquid-crystalline state) and, to a lesser extent, with the zwitterionic model membrane.
authors.affiliation: Associated Unity to the CSIC, Peptides and Proteins: Physical Chemistry Studies, Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, Av. Joan XXIII, s/n 08028 Barcelona, Spain.
authors.forename: Maite
authors.initials: M
authors.lastname: Alay
authors.forename: M
authors.initials: M
authors.lastname: Asunción Alsina
authors.forename: Isabel
authors.initials: I
authors.lastname: Haro
authors.forename: Josefina
authors.initials: J
authors.lastname: Prat
authors.forename: M Antònia
authors.initials: MA
authors.lastname: Busquets
mesh_terms: D016880:Anisotropy; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D008051:Lipid Bilayers / Q000737:chemistry*; D049449:Luminescence; D008956:Models, Chemical; D010455:Peptides / Q000737:chemistry*; D012680:Sensitivity and Specificity; D013696:Temperature; D014759:Viral Envelope Proteins / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D010455:Peptides; D014759:Viral Envelope Proteins; C107619:glycoprotein E2, GB virus C