title: Beta-helical fibrils from a model peptide.
abstract: A synthetic peptide, KLEG13 (Ac-KLKLKLELELELG-NH2), composed of alternating bulky hydrophilic and hydrophobic amino acid residues formed clear, viscous dispersions of fibrils in saline solutions. The fibrils had a uniform diameter of 2 nm as measured on electron micrographs of negatively stained preparations. 13C solid-state nuclear magnetic resonance spectroscopy of the fibrils indicated the presence of a beta-conformation. Circular dichroic spectra of the dispersion of fibrils were essentially identical to the calculated spectrum of a 100% beta-helix. Space-filling CPK models of a proposed beta-helical conformation of the peptide, in which the leucine side chains form a hydrophobic core and the hydrophilic lysine and glutamate side chains extend outwards from the helix, had a diameter consistent with the observed 2-nm diameter of the fibrils. This study may have implications regarding the structure of amyloid fibrils.
authors.affiliation: Department of Dermatology, The University of Iowa College of Medicine, Iowa City 52242, USA. nlazo@blue.weeg.uiowa.edu
authors.forename: N D
authors.initials: ND
authors.lastname: Lazo
authors.forename: D T
authors.initials: DT
authors.lastname: Downing
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008854:Microscopy, Electron; D008958:Models, Molecular; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D017433:Protein Structure, Secondary
chemical_list: C106799:KLEG13 peptide; D009842:Oligopeptides