Rampant Exchange of the Structure and Function of Extramembrane Domains between Membrane and Water Soluble Proteins
(A) Phylogenetic distribution of soluble proteins that share similar structure with membrane proteins. Phylogenetic distribution was sorted by sequence identity of membrane and soluble proteins. For three groups divided by sequence identity between membrane and soluble proteins (low: 0–20%, medium: 20–40% and high: 40–80%), the fraction of eukaryotic and prokaryotic orthologues was represented. (B) Functional enrichment of membrane and soluble protein structure pairs. Three groups divided by their sequence identity were analyzed for enrichment of gene ontology. Circles of each functional term were colored by their P-value. The fraction of proteins which are included in each functional term is proportional to the diameter of the circles.