Simultaneous measurement of 1HC/N-R2′s for rapid acquisition of backbone and sidechain paramagnetic relaxation enhancements (PREs) in proteins

Abstract

Paramagnetic relaxation enhancements (PREs) are routinely used to provide long-range distance restraints for the determination of protein structures, to resolve protein dynamics, ligand–protein binding sites, and lowly populated species, using Nuclear Magnetic Resonance Spectroscopy (NMR). Here, we propose a simultaneous ¹H-¹⁵?N, ¹H-¹³C SESAME based pulse scheme for the rapid acquisition of ¹H^C/N-R₂ relaxation rates for the determination of backbone and sidechain PREs of proteins. The ¹H^N-R₂ rates from the traditional and our approach on Ubiquitin (UBQ) are well correlated (R²?=?0.99), revealing their potential to be used quantitatively. Comparison of the S57C UBQ calculated and experimental PREs provided backbone and side chain Q factors of 0.23 and 0.24, respectively, well-fitted to the UBQ NMR structure, showing that our approach can be used to acquire accurate PRE rates from the functionally important sites of proteins but in at least half the time as traditional methods.