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PIP 2 Phospholipid‐Induced Aggregation of Tau Filaments Probed by Tip‐Enhanced Raman Spectroscopy
Author(s) -
Talaga David,
Smeralda Willy,
Lescos Laurie,
Hunel Julien,
LepejovaCaudy Nad'a,
Cullin Christophe,
Bonhommeau Sébastien,
Lecomte Sophie
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201809636
Subject(s) - chemistry , phospholipid , random coil , raman spectroscopy , membrane , amide , biophysics , protein secondary structure , nanoscopic scale , spectroscopy , crystallography , circular dichroism , nanotechnology , biochemistry , materials science , physics , optics , biology , quantum mechanics
The morphology and secondary structure of peptide fibers formed by aggregation of tubulin‐associated unit (Tau) fragments (K18), in the presence of the inner cytoplasmic membrane phosphatidylinositol component (PIP 2 ) or heparin sodium (HS) as cofactors, are determined with nanoscale (<10 nm) spatial resolution. By means of tip‐enhanced Raman spectroscopy (TERS), the inclusion of PIP 2 lipids in fibers is determined based on the observation of specific C=O ester vibration modes. Moreover, analysis of amide I and amide III bands suggests that the parallel β‐sheet secondary structure content is lower and the random coil content is higher for fibers grown from the PIP 2 cofactor instead of HS. These observations highlight the occurrence of some local structural differences between these fibers. This study constitutes the first nanoscale structural characterization of Tau/phospholipid aggregates, which are implicated in deleterious mechanisms on neural membranes in Alzheimer's disease.