title: Secondary structure in de novo designed peptides induced by electrostatic interaction with a lipid bilayer membrane.
abstract: We show that it is possible to induce a defined secondary structure in de novo designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solution, and results from far-UV circular dichroism spectroscopy demonstrate that the structure induced by the interaction with silica nanoparticles is solely alpha-helical and also strongly pH-dependent. The present study shows that negatively charged vesicles, to which the peptides are electrostatically adsorbed via cationic amino acid residues, induce either alpha-helices or beta-sheets and that the conformation is dependent on both lipid composition and variations in peptide primary structure. The pH-dependence of the vesicle-induced peptide secondary structure is weak, which correlates well with small differences in the vesicles' electrophoretic mobility, and thus the surface charge, as the pH is varied.
authors.affiliation: Division of Molecular Physics, IFM, Department of Physics, Chemistry and Biology, Linköping University, SE-581 83 Linköping, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Nygren
authors.forename: Martin
authors.initials: M
authors.lastname: Lundqvist
authors.forename: Bo
authors.initials: B
authors.lastname: Liedberg
authors.forename: Bengt-Harald
authors.initials: BH
authors.lastname: Jonsson
authors.forename: Thomas
authors.initials: T
authors.lastname: Ederth
mesh_terms: D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D002942:Circular Dichroism; D015195:Drug Design; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism*; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D010715:Phosphatidylglycerols / Q000378:metabolism; D055550:Protein Stability; D017433:Protein Structure, Secondary; D012542:Scattering, Radiation; D012822:Silicon Dioxide / Q000737:chemistry; D055672:Static Electricity; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D008051:Lipid Bilayers; D010455:Peptides; D010715:Phosphatidylglycerols; C051388:1,2-dioleoyl-sn-glycero-3-phosphoglycerol; D012822:Silicon Dioxide