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Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy
Author(s) -
Nagaraj Madhu,
Franks Trent W.,
Saeidpour Siavash,
Schubeis Tobias,
Oschkinat Hartmut,
Ritter Christiane,
van Rossum BarthJan
Publication year - 2016
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201600185
Subject(s) - thioflavin , nuclear magnetic resonance spectroscopy , chemistry , spectroscopy , nmr spectra database , isothermal titration calorimetry , nuclear magnetic resonance , tetramer , relaxation (psychology) , analytical chemistry (journal) , spectral line , stereochemistry , organic chemistry , medicine , physics , disease , pathology , quantum mechanics , astronomy , alzheimer's disease , enzyme , psychology , social psychology
Dynamic nuclear polarization (DNP) NMR can enhance sensitivity but often comes at the price of a substantial loss of resolution. Two major factors affect spectral quality: low‐temperature heterogeneous line broadening and paramagnetic relaxation enhancement (PRE) effects. Investigations by NMR spectroscopy, isothermal titration calorimetry (ITC), and EPR revealed a new substantial affinity of TOTAPOL to amyloid surfaces, very similar to that shown by the fluorescent dye thioflavin‐T (ThT). As a consequence, DNP spectra with remarkably good resolution and still reasonable enhancement could be obtained at very low TOTAPOL concentrations, typically 400 times lower than commonly employed. These spectra yielded several long‐range constraints that were difficult to obtain without DNP. Our findings open up new strategies for structural studies with DNP NMR spectroscopy on amyloids that can bind the biradical with affinity similar to that shown towards ThT.