The topological features of nonessential-nonhub proteins in the protein-protein interaction network

One of the important problems in system biology is to discover the relationship between topological properties and functional features of proteins in protein-protein interaction (PPI) networks. There are many essential-nonhub proteins and lots of nonessential-nonhub proteins in the PPI network. Both essential-nonhub proteins and nonessential-nonhub proteins are low-connectivity proteins, but they have different lethality. In order to explain why nonessential-nonhub proteins are not essential, we compare them with essential-nonhub proteins from topological view. The comparison results show that there are statistical differences between nonessential-nonhub proteins and essential-nonhub proteins in centrality measures and clustering coefficient.