1tgqA (labelled NS0), is the query protein that was selected for the all-α class. The first 4 characters correspond to the PDB code, the uppercase letter to the chain name and the last digit to the SCOP domain number, if any. The template structures that are used for the models are shown clockwise (they are labelled with the corresponding model name). FROST: is the FROST score. S
that defines the beginning of the twilight zone (see Fig. 1) is equal to 15. VAST: is the VAST score. A VAST score greater than 2 is indicative of a clear structural similarity. Below this value the structural relationship is unclear. TM: is the TM-score value. A value larger than 0.4 indicates that the proteins are structurally related, a value less than 0.17 that they are not related and a value in between corresponds to a zone were the structural relationship between the proteins is ambiguous. RMSd: is the Root Mean Square displacement value in Å between the corresponding model and the query native structure.