Fig. 5. : DSSPcont state-transitions. A residue assigned the state c by DSSP will typically have some probability for another state s' when using a continuous assignment. The other states {s'} are characterised by the average flow (eqn. 6). For example, the most likely alternative assignment to a-helix (H on x-axis) is T for both X-ray homologues (a) and NMR models (b, letter height describes the average flow). This result was obtained because DSSP assigns T for single hydrogen bonded helices. In particular, we noticed that the X-ray homologues were more inconsistent than the NMR models, as indicated not only by a larger average flow (y-axis) for a-helix (H) and b-strand (E), but also because flows between helix and strand are observed only for the X-ray data set.