Structural disorder of proteins in prokaryotic and eukaryotic species. (a) Average structural disorder in prokaryotes and eukaryotes was predicted by the IUPred algorithm , averaged over all proteins in the proteome, and is shown as a function of biological complexity of the species. (b) Species were grouped into six clusters and average disorder within these groups was calculated (error bars represent standard deviation). (c) Proteins were sorted on the basis of their Structural Classification of Proteins (SCOP)  domain expansions and their average disorder is shown as a function of biological complexity of the species. In particular, there are proteins in which domain expansion correlates (red circle) or does not correlate (green square) with biological complexity. For comparison, proteins are also shown that contain any kind of SCOP domain (blue triangle).
Schad et al. Genome Biology 2011 12:R120 doi:10.1186/gb-2011-12-12-r120