Excited States of Nucleic Acids Probed by Proton Relaxation Dispersion NMR Spectroscopy. Issue 39 (17th August 2016)

• Record Type: Journal Article
• Authors: Juen, Michael Andreas; Wunderlich, Christoph Hermann; Nußbaumer, Felix; Tollinger, Martin; Kontaxis, Georg; Konrat, Robert; Hansen, D. Flemming; Kreutz, Christoph
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 39(2016)
• Page Start: 12008
• Page End: 12012
• Publication Date: 2016-08-17
• Subjects: DNA -- NMR spectroscopy -- proton relaxation dispersion -- RNA -- stable isotope labeling; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201605870
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: In this work an improved stable isotope labeling protocol for nucleic acids is introduced. The novel building blocks eliminate/minimize homonuclear 13 C and 1 H scalar couplings thus allowing proton relaxation dispersion (RD) experiments to report accurately on the chemical exchange of nucleic acids. Using site‐specific 2 H and 13 C labeling, spin topologies are introduced into DNA and RNA that make 1 H relaxation dispersion experiments applicable in a straightforward manner. The novel RNA/DNA building blocks were successfully incorporated into two nucleic acids. The A‐site RNA was previously shown to undergo a two site exchange process in the micro‐ to millisecond time regime. Using proton relaxation dispersion experiments the exchange parameters determined earlier could be recapitulated, thus validating the proposed approach. We further investigated the dynamics of the cTAR DNA, a DNA transcript that is involved in the viral replication cycle of HIV‐1. Again, an exchange process could be characterized and quantified. This shows the general applicablility of the novel labeling scheme for 1 H RD experiments of nucleic acids. Abstract : Excited protons : Nucleotide chemistry and state of the art NMR methods are combined to probe excited states of RNA and DNA via proton relaxation dispersion experiments. The approach will be very useful for the elucidation of high‐resolution excited state structures of nucleic acids.