Gale Rhodes Welcome to the molecular level.
The variations illustrated in the figure represent uncertainty in our knowledge of this molecular structure . Structure determination of a macromolecule by NMR yields not one model, but a set, called an ensemble . Each frame in this animation is one model that fits all the NMR observations. In regions where the models agree with each other, the molecule is apparently well ordered and the models are well constrained by NMR data. Perhaps each model really does represent a conformation that the molecule can adopt in solution, or perhaps additional NMR data would reduce the variations.