Faithful estimation of dynamics parameters from CPMG relaxation dispersion measurements.
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.
Kovrigin
Evgenii L
EL
Department of Chemistry, Yale University, P.O. Box 208107, New Haven, CT 06520, USA.
Kempf
James G
JG
Grey
Michael J
MJ
Loria
J Patrick
JP
D000465:Algorithms; D008958:Models, Molecular; D015233:Models, Statistical; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods*; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*
D011506:Proteins