The magnetization exchange between two groups of equivalent spins each having different populations and overall relaxation rates has been analyzed. The results suggest that either the spin population difference or the overall relaxation rate difference in an exchange spectrum can produce cross-peaks with volumes larger than that of the corresponding diagonal line. This is important for interpretation of the magnetization exchange between water and macromolecular protons where both the population differences and auto-relaxation rate differences can be very large. Theoretical predictions of peak volume evolution were experimentally verified in the intermolecular magnetization exchange between the water and labile amide proton in a model system N-acetylglycine/water.
Elucidation of Deceptively Slow Magnetization Exchange between Protein Labile Protons and Water by Dilution-Enhanced Exchange Spectroscopy
Journal of the American Chemical Society | July 26, 2002 | Volume: 120 | Issue: 38 | Pages: 9963-9964
Least-Squares Method for Quantitative Determination of Chemical Exchange and Cross-Relaxation Rate Constants from a Series of Two-Dimensional Exchange NMR Spectra
The Journal of Physical Chemistry A | July 26, 2002 | Volume: 101 | Issue: 20 | Pages: 3707-3710