title: Spectroscopic evidence for the existence of an obligate pre-fibrillar oligomer during glucagon fibrillation.
abstract: The 29-residue peptide hormone glucagon has been used as a model system for the study of amyloid-like fibrils. Atomic force microscopy (AFM) studies have detected putative oligomeric species during this lag phase, but this has not been confirmed by any spectroscopic technique. Here we use an attached pyrene group to detect association (excimer formation) between individual glucagon molecules. Our data show that excimer formation precedes fibrillation both at different pHs and with sulfate, and support our original proposal that glucagon fibril formation is preceded by oligomer formation. We suggest that pyrene-labelling may be a useful way to monitor oligomer formation during protein fibrillation.
authors: Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK - 8000 Aarhus C, Denmark.
authors: Peter Astrup
authors: PA
authors: Christensen
authors: Jesper Søndergaard
authors: JS
authors: Pedersen
authors: Gunna
authors: G
authors: Christiansen
authors: Daniel Erik
authors: DE
authors: Otzen
mesh_terms: D001704:Biopolymers / Q000737:chemistry*; D005934:Glucagon / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D013050:Spectrometry, Fluorescence
chemical_list: D001704:Biopolymers; D005934:Glucagon