Hubs and Non-Hubs in Protein-Protein Interaction Networks: A Biophysical Interpretation

The main characteristic of biological networks is scale freeness which is distinguished by the power-law degree distribution of the edges per node. Hubs play a central role in different biological process. In this study we compared hub and non-hub proteins in Saccharomyces cerevisiae protein-protein interaction network by their size, primary and secondary structure properties and their genes distribution along chromosomes. The results show that hubs are larger than non-hubs and substitution of aliphatic, hydrophobic and aromatic groups of amino acids with acidic, charged and hydrophilic groups of amino acids in protein chains from non-hub to hub proteins is one of the mechanisms of highly connectivity.