Revealing weak histidine ¹⁵N homonuclear scalar couplings using Solid-State Magic-Angle-Spinning NMR spectroscopy.

ABSTRACT: The tautomeric structure and chemistry of the histidine imidazole ring play active roles in many structurally and functionally important proteins and polypeptides. While in NMR spectroscopy histidine chemical shifts (e.g. ¹⁵N, ¹³C, and ¹H) have been commonly used to characterize the tautomeric structure, hydrogen bonding, and torsion angles, homonuclear ¹⁵N scalar couplings in histidine have rarely been reported. Here, we propose double spin-echo sequences to compare the observed signals with and without a 90° pulse between the two spin-echo periods, such that their signal ratio as a function of the echo time solely depends on homonuclear scalar couplings, allowing for measuring weak homonuclear scalar couplings without influence from transverse

SUBMITTER: Tan C 

PROVIDER: S-EPMC7426724 | biostudies-literature | 2020 Jul

REPOSITORIES: biostudies-literature