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Segmental 13 C‐Labeling and Raman Microspectroscopy of α‐Synuclein Amyloid Formation
Author(s) -
Flynn Jessica D.,
Jiang Zhiping,
Lee Jennifer C.
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201809865
Subject(s) - chemistry , thioflavin , raman spectroscopy , amyloid (mycology) , monomer , conformational change , fluorescence , crystallography , biophysics , stereochemistry , polymer , alzheimer's disease , medicine , inorganic chemistry , physics , disease , organic chemistry , pathology , biology , optics , quantum mechanics
Mapping conformational changes of α‐synuclein (α‐syn) from soluble, unstructured monomers to β‐sheet‐ rich aggregates is crucial towards understanding amyloid formation. Raman microspectroscopy is now used to spatially resolve conformational heterogeneity of amyloid aggregates and monitor amyloid formation of segmentally 13 C‐labeled α‐syn in real‐time. As the 13 C‐isotope shifts the amide‐I stretching frequency to lower energy, the ligated construct, 13 C 1–86 12 C S87C–140 ‐α‐syn, exhibits two distinct bands allowing for simultaneous detection of secondary structural changes in N‐terminal 1–86 and C‐terminal 87–140 residues. The disordered‐to‐β‐sheet conformational change is first observed for the N‐terminal followed by the C‐terminal region. Finally, Raman spectroscopic changes occurred prior to Thioflavin T fluorescence enhancement, indicating that the amide‐I band is a superior probe of amyloid formation.