Conventional NMR structure bundles are not thermodynamic ensembles

Summary

Conventional deposited NMR structure bundles are not Boltzmann-weighted thermodynamic ensembles (1). They are sets of independently calculated models consistent with the experimental restraints, and their spread often reflects structural uncertainty rather than conformer populations. Ensemble-averaged NMR restraints can, however, be integrated with simulations to construct dynamics-bearing ensembles (2).

See also

• Cryo-EM particle counting does not reliably provide true Boltzmann distributions of molecules

1.

Reinknecht C, Riga A, Rivera J, Snyder DA. Patterns in Protein Flexibility: A Comparison of NMR “Ensembles”, MD Trajectories, and Crystallographic B-Factors. Molecules. 2021;26(5):1484. Available from: https://doi.org/10.3390/molecules26051484

2.

Lindorff-Larsen K, Best RB, DePristo MA, Dobson CM, Vendruscolo M. Simultaneous determination of protein structure and dynamics. Nature. 2005;433(7022):128–32. Available from: https://doi.org/10.1038/nature03199