Figure 4.

Definition of states, conformers, and ensembles. (Top) Shown are two different states of a theoretical protein, with each individual state being defined as one set of coordinates for all the atoms of a molecule. Structure calculation using this data would result in a single conformer that satisfied the data well and could be composed of one or more states; (Middle) The structure calculation is repeated multiple times, resulting in many conformers; (Bottom) Finally, the ensemble is the superposition of all of the conformers. If multiple states were allowed in the structure calculation, then the ensemble could be divided into sub-bundles, each of which would be identified by structural similarity in the region of interest, which corresponds to a single state.