title: Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy.
abstract: 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.
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125, Berlin, Germany.
authors.forename: Madhu
authors.initials: M
authors.lastname: Nagaraj
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125, Berlin, Germany.
authors.forename: Trent W
authors.initials: TW
authors.lastname: Franks
authors.affiliation: Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, 14195, Berlin, Germany.
authors.forename: Siavash
authors.initials: S
authors.lastname: Saeidpour
authors.affiliation: Helmholtz-Zentrum für Infektionsforschung (HZI), Inhoffenstrasse 7, 38124, Braunschweig, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schubeis
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125, Berlin, Germany.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Oschkinat
authors.affiliation: Helmholtz-Zentrum für Infektionsforschung (HZI), Inhoffenstrasse 7, 38124, Braunschweig, Germany.|SeNostic GmbH, Feodor-Lynen-Strasse 21, 30625, Hannover, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Ritter
authors.affiliation: Leibniz-Institut für Molekulare Pharmakologie (FMP), Robert-Rössle-Strasse 10, 13125, Berlin, Germany. brossum@fmp-berlin.de.
authors.forename: Barth-Jan
authors.initials: BJ
authors.lastname: van Rossum
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D000818:Animals; D001665:Binding Sites; D003497:Cyclic N-Oxides / Q000737:chemistry*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D015394:Molecular Structure; D020005:Propanols / Q000737:chemistry*; D013499:Surface Properties
chemical_list: C521769:1-(TEMPO-4-oxy)-3-(TEMPO-4-amino)propan-2-ol; D000682:Amyloid; D003497:Cyclic N-Oxides; D020005:Propanols
keywords: NMR spectroscopy; biradical binding; curli amyloid; dynamic nuclear polarization NMR; protein structures