Faithful estimation of dynamics parameters from CPMG relaxation dispersion measurements

J Magn Reson. 2006 May;180(1):93-104. doi: 10.1016/j.jmr.2006.01.010. Epub 2006 Feb 3.


This work examines the robustness of fitting of parameters describing conformational exchange (k(ex), p(a/b), and Deltaomega) processes from CPMG relaxation dispersion data. We have analyzed the equations describing conformational exchange processes for the intrinsic inter-dependence of their parameters that leads to the existence of multiple equivalent solutions, which equally satisfy the experimental data. We have used Monte-Carlo simulations and fitting to the synthetic data sets as well as the direct 3-D mapping of the parameter space of k(ex), p(a/b), and Deltaomega to quantitatively assess the degree of the parameter inter-dependence. The demonstrated high correlation between parameters can preclude accurate dynamics parameter estimation from NMR spin-relaxation data obtained at a single static magnetic field. The strong parameter inter-dependence can readily be overcome through acquisition of spin-relaxation data at more than one static magnetic field thereby allowing accurate assessment of conformational exchange properties.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Algorithms
  • Models, Molecular
  • Models, Statistical
  • Nuclear Magnetic Resonance, Biomolecular / methods*
  • Protein Conformation
  • Proteins / chemistry*


  • Proteins