title: Peptide stabilized amphotericin B nanodisks.
abstract: Nanometer scale apolipoprotein A-I stabilized phospholipid disk complexes (nanodisks; ND) have been formulated with the polyene antibiotic amphotericin B (AMB). The present studies were designed to evaluate if a peptide can substitute for the function of the apolipoprotein component of ND with respect to particle formation and stability. An 18-residue synthetic amphipathic alpha-helical peptide, termed 4F (Ac-D-W-F-K-A-F-Y-D-K-V-A-E-K-F-K-E-A-F-NH(2)), solubilized vesicles comprised of egg phosphatidylcholine (egg PC), dipentadecanoyl PC or dimyristoylphosphatidylcholine (DMPC) at rates greater than or equal to solubilization rates observed with human apolipoprotein A-I (apoA-I; 243 amino acids). Characterization studies revealed that interaction with DMPC induced a near doubling of 4F tryptophan fluorescence emission quantum yield (excitation 280 nm) and a approximately 7 nm blue shift in emission wavelength maximum. Inclusion of AMB in the vesicle substrate resulted in formation of 4F AMB-ND. Spectra of AMB containing particles revealed the antibiotic is a highly effective quencher of 4F tryptophan fluorescence emission, giving rise to a Ksv=7.7 x 10(4). Negative stain electron microscopy revealed that AMB-ND prepared with 4F possessed a disk shaped morphology similar to ND prepared without AMB or prepared with apoA-I. In yeast and pathogenic fungi growth inhibition assays, 4F AMB-ND was as effective as apoA-I AMB-ND. The data indicate that AMB-ND generated using an amphipathic peptide in lieu of apoA-I form a discrete population of particles that possess potent biological activity. Given their intrinsic versatility, peptides may be preferred for scale up and clinical application of AMB-ND.
authors.affiliation: Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr. Way, Oakland, CA 94609, USA.
authors.forename: Megan
authors.initials: M
authors.lastname: Tufteland
authors.forename: Joseph B
authors.initials: JB
authors.lastname: Pesavento
authors.forename: Rachelle L
authors.initials: RL
authors.lastname: Bermingham
authors.forename: Paul D
authors.initials: PD
authors.lastname: Hoeprich
authors.forename: Robert O
authors.initials: RO
authors.lastname: Ryan
mesh_terms: D000595:Amino Acid Sequence; D000666:Amphotericin B / Q000737:chemistry* / Q000494:pharmacology; D000935:Antifungal Agents / Q000737:chemistry* / Q000494:pharmacology; D016632:Apolipoprotein A-I / Q000737:chemistry / Q000494:pharmacology; D001232:Aspergillus fumigatus / Q000187:drug effects / Q000254:growth & development; D002176:Candida albicans / Q000187:drug effects / Q000254:growth & development; D003455:Cryptococcus neoformans / Q000187:drug effects / Q000254:growth & development; D046529:Microscopy, Electron, Transmission; D008956:Models, Chemical; D008969:Molecular Sequence Data; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology; D010743:Phospholipids / Q000737:chemistry; D013050:Spectrometry, Fluorescence
chemical_list: D000935:Antifungal Agents; D016632:Apolipoprotein A-I; D010455:Peptides; D010743:Phospholipids; D000666:Amphotericin B