Figure 17. The Rc metric used to assess fit of predicted contacts to a model.
The expected total GREMLIN score if the structure was native was estimated by summing sco*P(contact|sco, seq, len, sep) over all contacts with sep ≥6. To evaluate the fit of a particular model to a predicted contact set, we take the ratio of the actual total GREMLIN score of the model to the expected total score computed as above; we refer to this ratio of observed and expected contact scores as ‘Rc’. Blue line: the distribution of Rc in native structures with 4L–10L sequences; Red line: distribution of Rc after randomly reassigning contact predictions to structures. Rc values less than 0.7 are very infrequently observed for native structures; we use this value as a cutoff to evaluate the fit of a predicted contact set to a model.