title: Formation and stability of nanofibers from a milk-derived peptide.
abstract: The objective of the present work was to investigate the physicochemical conditions that trigger the self-assembly of peptide β-lg f1-8 and therefore lead to nanofibers and hydrogel formation. Nanostructures formed by self-assembly of peptide β-lg f1-8 in the pH range of 2.0-11.0 were studied by transmission electron microscopy (TEM). Hydrogel formation was studied as a function of pH and resulted in evidence of a link between hydrogel formation and the charge distribution carried by the peptide structure. Finally, circular dichroism (CD) spectroscopy was used to characterize the effects of peptide concentration (0.4-2.0 mg/mL), ionic strength (0-1 M NaCl), and temperature (20-80 °C) on the secondary structure of peptide β-lg f1-8. Hydrogels were obtained at peptide concentrations above 2.5 mg/mL. Peptide concentration and pH adjustment were shown to trigger self-assembly of β-lg f1-8, but increasing ionic strength had no effect. Heating to 80 °C induced a stronger CD signal intensity due to an increase in solubility of the peptide, whereas only slight changes in CD pattern were found upon cooling to 20 °C. Overall, results emphasize the role of particular molecular interactions in β-sheet self-assembly of peptide β-lg f1-8 and pH-dependent electrostatic interactions occurring between β-lg f1-8 units, which can explain its propensity to self-assembly.
authors.affiliation: STELA Dairy Research Center, Institute of Nutraceuticals and Functional Foods, Université Laval, Quebec City, QC, Canada G1V0A6.
authors.forename: Marie-Michèle
authors.initials: MM
authors.lastname: Guy
authors.forename: Mélanie
authors.initials: M
authors.lastname: Tremblay
authors.forename: Normand
authors.initials: N
authors.lastname: Voyer
authors.forename: Sylvie F
authors.initials: SF
authors.lastname: Gauthier
authors.forename: Yves
authors.initials: Y
authors.lastname: Pouliot
mesh_terms: D000818:Animals; D002417:Cattle; D006863:Hydrogen-Ion Concentration; D008892:Milk / Q000737:chemistry*; D057139:Nanofibers / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*
chemical_list: D010455:Peptides