title: Surface behavior of peptides from E1 GBV-C protein: Interaction with anionic model membranes and importance in HIV-1 FP inhibition.
abstract: The interaction between a peptide sequence from GB virus C E1 protein (E1P8) and its structural analogs (E1P8-12), (E1P8-13), and (E1P8-21) with anionic lipid membranes (POPG vesicles and POPG, DPPG or DPPC/DPPG (2:1) monolayers) and their association with HIV-1 fusion peptide (HIV-1 FP) inhibition at the membrane level were studied using biophysical methods. All peptides showed surface activity but leakage experiments in vesicles as well as insertion kinetics in monolayers and lipid/peptide miscibility indicated a low level of interaction: neither E1P8 nor its analogs induced the release of vesicular content and the exclusion pressure values (πe) were clearly lower than the biological membrane pressure (24-30 mN m(-1)) and the HIV-1 FP (35 mN m(-1)). Miscibility was elucidated in terms of the additivity rule and excess free energy of mixing (GE). E1P8, E1P8-12 and E1P8-21 (but not E1P8-13) induced expansion of the POPG monolayer. The mixing process is not thermodynamically favored as the positive GE values indicate. To determine how E1 peptides interfere in the action of HIV-1 FP at the membrane level, mixed monolayers of HIV-1 FP/E1 peptides (2:1) and POPG were obtained. E1P8 and its derivative E1P8-21 showed the greatest HIV-1 FP inhibition. The LC-LE phase lipid behavior was morphologically examined via fluorescence microscopy (FM) and atomic force microscopy (AFM). Images revealed that the E1 peptides modify HIV-1 FP-lipid interaction. This fact may be attributed to a peptide/peptide interaction as indicated by AFM results. Finally, hemolysis assay demonstrated that E1 peptides inhibit HIV-1 FP activity.
authors.affiliation: Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Galatola
authors.affiliation: Dept. de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, 28040 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Cruz
authors.affiliation: Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Gómara
authors.affiliation: Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, CSIC-Associated Unit: Peptides and Proteins: Physicochemical Studies, IN2UB Av. Joan XXIII s/n, 08028 Barcelona, Spain; Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Prat
authors.affiliation: Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, CSIC-Associated Unit: Peptides and Proteins: Physicochemical Studies, IN2UB Av. Joan XXIII s/n, 08028 Barcelona, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Alsina
authors.affiliation: Unit of Synthesis and Biomedical Application of Peptides, Department of Biomedical Chemistry, IQAC-CSIC, Jordi Girona 18, 08034, Barcelona, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Haro
authors.affiliation: Physical Chemistry Department, Faculty of Pharmacy, University of Barcelona, CSIC-Associated Unit: Peptides and Proteins: Physicochemical Studies, IN2UB Av. Joan XXIII s/n, 08028 Barcelona, Spain. Electronic address: mopujol@ub.edu.
authors.forename: M
authors.initials: M
authors.lastname: Pujol
mesh_terms: D040761:Biomimetic Materials; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects; D029407:GB virus C / Q000737:chemistry*; D015497:HIV-1 / Q000737:chemistry*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D007700:Kinetics; D008051:Lipid Bilayers / Q000737:chemistry*; D008567:Membranes, Artificial; D010715:Phosphatidylglycerols / Q000737:chemistry; D013816:Thermodynamics; D014759:Viral Envelope Proteins / Q000737:chemistry* / Q000494:pharmacology; D014760:Viral Fusion Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000494:pharmacology
chemical_list: C087035:E1 protein, Hepatitis C virus; D008051:Lipid Bilayers; D008567:Membranes, Artificial; D010715:Phosphatidylglycerols; D014759:Viral Envelope Proteins; D014760:Viral Fusion Proteins; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C030345:1,2-dipalmitoylphosphatidylglycerol
keywords: AFM; Fluorescence technique; GBV-C peptide; HIV-1 FP; Hemolysis; Lipid model membrane