Premium
Polarized Raman spectroscopy of aligned insulin fibrils
Author(s) -
Sereda Valentin,
Lednev Igor K.
Publication year - 2014
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4523
Subject(s) - fibril , raman spectroscopy , spectroscopy , crystallography , chemistry , polarization (electrochemistry) , materials science , amyloid fibril , peptide , biophysics , amyloid β , optics , biochemistry , physics , biology , quantum mechanics , medicine , disease , pathology
Amyloid fibrils are associated with many neurodegenerative diseases. The application of conventional techniques of structural biology, X‐ray crystallography and solution NMR, for fibril characterization is limited because of the noncrystalline and insoluble nature of the fibrils. Here, polarized Raman spectroscopy was used to determine the orientation of selected chemical groups in aligned insulin fibrils, specifically of peptide carbonyls. The methodology is solely based on the measurement of the change in Raman scattered intensity as a function of the angle between the incident laser polarization and the aligned fibrils. The order parameters 〈 P 2 〉 and 〈 P 4 〉 of the orientation distribution function were obtained, and the most probable distribution of C=O group orientation was calculated. The results indicate that the peptides' carbonyl groups are oriented at an angle of 13 ± 5° from the fibril axis, which is consistent with previously reported qualitative descriptions of an almost parallel orientation of the C=O groups relative to the main fibril axis. Copyright © 2014 John Wiley & Sons, Ltd.