Table 1. Topological characteristics of used PPI networks.

Network	# proteins	# interactions	cc	avNeighbors	density
Gavin	1359	6451	0.4196	9.49	0.0070
Krogan	2559	7031	0.1947	5.50	0.0021
Collins	1004	8319	0.6478	16.57	0.0165
BioGRID	5850	68312	0.2622	23.35	0.0040

Here cc denotes the average clustering coefficient of network, avNeighbors denotes the average number of neighbors of each protein.