Expedited NMR Assignment of Small- to Medium-Sized Molecules with Improved HSQC−CLIP−COSY Experiments

Tamás Gyöngyösi (1) , István Timári (1) , Davy Sinnaeve (2, 3) , Burkhard Luy (4) , Katalin E. Kövér (1)

1 University of Debrecen Egyetem [Debrecen]
2 ERL 9002 - BSI - Biologie Structurale Intégrative
3 RID-AGE - Facteurs de Risque et Déterminants Moléculaires des Maladies liées au Vieillissement - U 1167
4 KIT - Karlsruhe Institute of Technology

Resonance assignment is a pivotal step for any nuclear magnetic resonance (NMR) analysis, such as structure elucidation or the investigation of protein–ligand interactions. Both 1H-13C heteronuclear single quantum correlation (HSQC) and 1H-1H correlation spectroscopy (COSY) two-dimensional (2D) experiments are invaluable for 1H NMR assignment, by extending the high signal dispersion of 13C chemical shifts onto 1H resonances and by providing a high amount of through-bond 1H-1H connectivity information, respectively. The recently introduced HSQC−CLIP(Clean In-Phase)−COSY method combines these two experiments, providing COSY correlations along the high-resolution 13C dimension with clean in-phase multiplets. However, two experiments need to be recorded to unambiguously identify COSY cross-peaks. Here, we propose novel variants of the HSQC–CLIP–COSY pulse sequence that edit cross-peak signs so that direct HSQC responses can be distinguished from COSY relay peaks, and/or the multiplicities of the 13C nuclei are reflected, allowing the assignment of all the peaks in a single experiment. The advanced HSQC–CLIP–COSY variants have the potential to accelerate and simplify the NMR structure-elucidation process of both synthetic and natural products and to become valuable tools for high-throughput computer-assisted structure determination.

Mots clés: NMR; Peptides and proteins

Domaines: Chimie analytique

Tamás Gyöngyösi, István Timári, Davy Sinnaeve, Burkhard Luy, Katalin E. Kövér. Expedited NMR Assignment of Small- to Medium-Sized Molecules with Improved HSQC−CLIP−COSY Experiments. Analytical Chemistry, 2021, 93 (6), pp.3096-3102. ⟨10.1021/acs.analchem.0c04124⟩. ⟨hal-03328594⟩