Figure 4.

Going beyond three-state secondary structure. The structures related to methylglyoxal synthase (a) [PDB ID 2X8W] are identified purely based on the secondary structure, using SSEA server [142]. A different fold (b) (Response Regulator, PDB ID 1M5T) [143] was obtained as a top hit based on the secondary structure content. The secondary structure alignment (c) shows that the structures are close based on the secondary structure; however, the folds are different. The equivalent helices and strands are highlighted in the same colour in the two structures (a,b). A more precise description of the backbone conformation was obtained using PB (d). The assignment of PB instead of the three-state secondary structures highlights many differences between the two structures, which were otherwise masked by the secondary structure definition. The segments assigned as coils (indicated by ‘C’) are highlighted in red in the PB alignment. Other differences in the regular secondary structures are in blue. (Online version in colour.)