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Updated: Oct 3, 2026

Time-resolved ElectroSpray Ionization Hydrogen-deuterium Exchange Mass Spectrometry for Studying Protein Structure and Dynamics
Published on: April 17, 2017
Proton exchange as a relaxation mechanism for T1 in the rotating frame in native and immobilized protein solutions
H I Mäkelä1, O H Gröhn, M I Kettunen
1National Bio-NMR Facility, University of Kuopio, Kuopio, FIN-70211, Finland.
Abstract:
T1 relaxation in the rotating frame (T1rho) is a sensitive magnetic resonance imaging (MRI) contrast for acute brain insults. Biophysical mechanisms affecting T1rho relaxation rate (R1rho) and R1rho dispersion (dependency of R1rho on the spin-lock field) were studied in protein solutions by varying their chemical environment and pH in native, heat-denatured, and glutaraldehyde (GA) cross-linked samples. Low pH strongly reduced R1rho in heat-denatured phantoms displaying proton resonances from a number of side-chain chemical groups in high-resolution 1H NMR spectra. At pH of 5.5, R1rho dispersion was completely absent. In contrast, in the GA-treated phantoms with very few NMR visible side chain groups, acidic pH showed virtually no effect on R1rho. The present data point to a crucial role of proton exchange on R1rho and R1rho dispersion in immobilized protein solution mimicking tissue relaxation properties.
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