Robustness of Protein Complex Networks

The stability and fragility of four species' (rat, yeast, mouse, human) protein complex networks (PCNs) are studied by investigating their robustness, i.e. whether their global topological properties, especially average diameter, retain a similar system behavior with respect to four different types of perturbations or not. Four types of perturbations consist of : (i) network edges are randomly removed, (ii) network nodes are randomly deleted (failure), (iii) the most connected nodes are successively removed (attack), and (iv) interaction edges are randomly rewired. In the experiment of this paper, at most 40% of network nodes or edges are deleted or rewired. It is demonstrated that, except mouse organism and attack perturbation, the average diameters for perturbed networks differ from the unperturbed cases in less than 13%, which is small in comparison with WWW and the Internet results. That is, the protein complex networks of rat, yeast and human species are quite robust with respect to failure, rewiring and edge deletion perturbations, but not robust against the attack one.