title: Analysis of insulin amyloid fibrils by Raman spectroscopy.
abstract: The formation of amyloid fibrils from insulin is investigated using drop-coating-deposition-Raman (DCDR) difference spectroscopy and atomic force microscopy (AFM). Fibrils formed using various co-solvents and heating cycles are found to induce the appearance of Raman difference peaks in the amide I (approximately 1675 cm(-1)), amide III (approximately 1220 cm(-1)), and peptide backbone (approximately 1010 cm(-1)), consistent with an increase in beta-sheet content. Comparisons of results obtained from fibrils in either H2O or D2O suggest that the NH/ND stretch bands (at approximately 3300 cm(-1)/ approximately 2400 cm(-1)) are also enhanced in intensity upon fibril formation. If there is any water trapped in the core of the fibrils its OH/OD Raman intensity is too small to be detected in the presence of the stronger NH/ND bands which appear in the same region. AFM is used to confirm the formation of fibrils of about 5 nm diameter (and various lengths).
authors: Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA.
authors: Corasi
authors: C
authors: Ortiz
authors: Dongmao
authors: D
authors: Zhang
authors: Alexander E
authors: AE
authors: Ribbe
authors: Yong
authors: Y
authors: Xie
authors: Dor
authors: D
authors: Ben-Amotz
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D007328:Insulin / Q000737:chemistry*; D013054:Spectrophotometry, Atomic; D013059:Spectrum Analysis, Raman
chemical_list: D000682:Amyloid; D007328:Insulin