Measurement of Angstrom to Nanometer Molecular Distances with 19F Nuclear Spins by EPR/ENDOR Spectroscopy. Issue 1 (13th November 2019)

• Record Type: Journal Article
• Authors: Meyer, Andreas; Dechert, Sebastian; Dey, Surjendu; Höbartner, Claudia; Bennati, Marina
• Is Part Of: Angewandte Chemie international edition. Volume 59:Issue 1(2020)
• Page Start: 373
• Page End: 379
• Publication Date: 2019-11-13
• Subjects: fluorine -- high field ENDOR -- RNA -- spin labelling -- structural biology; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201908584
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Spectroscopic and biophysical methods for structural determination at atomic resolution are fundamental in studies of biological function. Here we introduce an approach to measure molecular distances in bio‐macromolecules using 19 F nuclear spins and nitroxide radicals in combination with high‐frequency (94 GHz/3.4 T) electron–nuclear double resonance (ENDOR). The small size and large gyromagnetic ratio of the 19 F label enables to access distances up to about 1.5 nm with an accuracy of 0.1–1 Å. The experiment is not limited by the size of the bio‐macromolecule. Performance is illustrated on synthesized fluorinated model compounds as well as spin‐labelled RNA duplexes. The results demonstrate that our simple but strategic spin‐labelling procedure combined with state‐of‐the‐art spectroscopy accesses a distance range crucial to elucidate active sites of nucleic acids or proteins in the solution state. Abstract : What did the NO say to the 19 F? Dipolar couplings between nitroxide spin labels and 19 F nuclear spins report inter‐spin distances in the range of ≲15 Å at sub‐angstrom accuracy. These couplings are measured with sub‐nanomole spin sensitivity by high frequency (94 GHz) electron–nuclear double resonance (ENDOR) and can be employed to obtain detailed structural insights into biomolecules.