Table 4.

DDI-PPI mapping based on both single domain PPIs and the structural DDIs

Organisma	E. coli	yeast	worm	fly	human
Number of PPIs	6,934	24,699	5,315	24,703	28,800
Number of PPIs with known domains (N)	6,038	18,202	3,351	14,939	25,004
Number of PPIs to which DDIs could be mapped (n) (%; n/N*100)	1,234 (20%)	5,048 (28%)	860 (26%)	3,983 (27%)	7,991 (32%)

^a Organism labeling: yeast: S. cerevisiae, worm: C. elegans, fly: D. melanogaster. DDI, domain-domain interaction; PPI, protein-protein interaction.