The Chemical Shift Baseline for High‐Pressure NMR Spectra of Proteins. Issue 30 (10th June 2016)

• Record Type: Journal Article
• Authors: Frach, Roland; Kibies, Patrick; Böttcher, Saraphina; Pongratz, Tim; Strohfeldt, Steven; Kurrmann, Simon; Koehler, Joerg; Hofmann, Martin; Kremer, Werner; Kalbitzer, Hans Robert; Reiser, Oliver; Horinek, Dominik; Kast, Stefan M.
• Is Part Of: Angewandte Chemie international edition. Volume 55:Issue 30(2016)
• Page Start: 8757
• Page End: 8760
• Publication Date: 2016-06-10
• Subjects: computational chemistry -- high-pressure chemistry -- isotopes -- NMR spectroscopy -- proteins; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201602054
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: High‐pressure (HP) NMR spectroscopy is an important method for detecting rare functional states of proteins by analyzing the pressure response of chemical shifts. However, for the analysis of the shifts it is mandatory to understand the origin of the observed pressure dependence. Here we present experimental HP NMR data on the 15 N‐enriched peptide bond model, N ‐methylacetamide (NMA), in water, combined with quantum‐chemical computations of the magnetic parameters using a pressure‐sensitive solvation model. Theoretical analysis of NMA and the experimentally used internal reference standard 4, 4‐dimethyl‐4‐silapentane‐1‐sulfonic (DSS) reveal that a substantial part of observed shifts can be attributed to purely solvent‐induced electronic polarization of the backbone. DSS is only marginally responsive to pressure changes and is therefore a reliable sensor for variations in the local magnetic field caused by pressure‐induced changes of the magnetic susceptibility of the solvent. Abstract : Solvent‐induced electronic polarization in high‐pressure NMR spectra of proteins: A pressurized polar solvent environment influences the electronic structure of both the reference standard and the target protein. Combined experimental and computational effort elucidates the pressure transparency of the common standard 4, 4‐dimethyl‐4‐silapentane‐1‐sulfonic acid (DSS, see picture) and the intrinsic, polarization‐related chemical shift of N ‐methylacetamide, a prototype of the protein backbone.