title: Self-assembly of peptides into spherical nanoparticles for delivery of hydrophilic moieties to the cytosol.
abstract: We report a novel class of self-assembling peptide nanoparticles formed by mixing aqueous solutions of K(16) peptide and a 20 amino acid peptide of net charge -5 (GLFEALLELLESLWELLLEA). Particle formation is salt-dependent and yields perfectly spherical nanoparticles of approximately 120 to approximately 800 nm diameter, depending on buffer composition and temperature, with a stoichiometry of approximately 1:2.5 for the cationic and anionic peptides. The anionic peptide forms an alpha-helix in aqueous solution, has all five glutamates on one side of the helix, and exists entirely as a discrete oligomer of 9-10 peptides. A rigid oligomer with 45-50 negative charges almost certainly represents the core component of these nanoparticles, held together by electrostatic interactions with the unstructured K(16) peptide. Cells internalize these particles by an endocytic process, and free particles are frequently seen in the cytosol, presumably because of the acid-dependent fusogenic properties of the anionic peptide. Among other applications, these particles have potential for the targeted delivery of single or multiple therapeutic moieties directly to the cytosol, and we report the successful delivery of a K(16)-linked pro-apoptosis peptide.
authors.affiliation: Department of Clinical Sciences, King's College London School of Medicine, James Black Centre, 125 Coldharbour Lane, London, England.
authors.forename: Louise
authors.initials: L
authors.lastname: Collins
authors.forename: Alan L
authors.initials: AL
authors.lastname: Parker
authors.forename: John D
authors.initials: JD
authors.lastname: Gehman
authors.forename: Lorna
authors.initials: L
authors.lastname: Eckley
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Perugini
authors.forename: Frances
authors.initials: F
authors.lastname: Separovic
authors.forename: John W
authors.initials: JW
authors.lastname: Fabre
mesh_terms: D000595:Amino Acid Sequence; D002460:Cell Line; D003600:Cytosol / Q000378:metabolism*; D004705:Endocytosis; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D057054:Molecular Imaging; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D010455:Peptides