Fig. S1.

(A) Proportion of pairs of proteins in the human protein–protein interaction network [214,806 heterodimeric interactions retrieved from BIOGRID (64)] containing interprotein domain interactions with solved structure (dark blue), having reliable structural templates (≥30% sequence identity, blue), with more than 500 prokaryotic nonredundant homologs (<80% sequence identity), and lacking an experimental structure or a reliable structural template (light blue). (B) Venn diagram for the three sets of human interactions with structural or evolutionary information.