title: Stepwise oligomerization of murine amylin and assembly of amyloid fibrils.
abstract: Amylin is a pancreatic hormone co-secreted with insulin. Human amylin has been shown to form dimers and exhibit high propensity for amyloid fibril formation. We observed the ability of the water-soluble murine amylin to aggregate in water resulting in an insoluble material with Thioflavin T binding properties. Infrared spectroscopy analysis revealed beta-sheet components in the aggregated murine amylin. Morphological analysis by transmission electron microscopy and atomic force microscopy provided access to the fibril nature of the murine amylin aggregate which is similar to amyloid fibrils from human amylin. X-ray diffraction of the murine amylin fibrils showed peaks at 4.7Å and 10Å, a fingerprint for amyloid fibrils. Electron spray ionization-ion mobility spectroscopy-mass spectrometry (ESI-IMS-MS) analysis and crosslinking assays revealed self-association intermediates of murine amylin into high order oligomeric assemblies. These data demonstrate the stepwise association mechanism of murine amylin into stable oligomers, which ultimately converges to its organization into amyloid fibrils.
authors: Laboratory for Pharmaceutical Biotechnology, School of Pharmacy, Federal University of Rio de Janeiro - UFRJ, CCS, Bss34, Ilha do Fundão, 21941-617 Rio de Janeiro, RJ, Brazil.
authors: Leonardo C
authors: LC
authors: Palmieri
authors: Bruno
authors: B
authors: Melo-Ferreira
authors: Carolina A
authors: CA
authors: Braga
authors: Giselle N
authors: GN
authors: Fontes
authors: Luana Jotha
authors: LJ
authors: Mattos
authors: Luís Maurício T R
authors: LM
authors: Lima
mesh_terms: D000682:Amyloid / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D052160:Benzothiazoles; D006801:Humans; D058228:Islet Amyloid Polypeptide / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D058105:Polymerization; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012996:Solutions / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013844:Thiazoles / Q000737:chemistry / Q000378:metabolism
chemical_list: D000682:Amyloid; D052160:Benzothiazoles; D058228:Islet Amyloid Polypeptide; D012996:Solutions; D013844:Thiazoles; C009462:thioflavin T
keywords: Amylin; Amyloid; Diabetes; ESI-IMS-MS; Electrospray Ionization–Ion Mobility Spectrometry–Mass Spectrometry; IAPP; Islet associated polypeptide; islet amyloid polypeptide