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Protein-protein interactions (PPIs) control variety of biological phenomena including development, cell to cell interactions and metabolic processes [1]. The PPIs can be classified into different groups, depending upon their functional and structural properties [2]. Depending upon their persistence,(1) they may be termed as permanent or transient, as characterized by their interaction surface,(2) they may be considered as heterooligomeric or homooligomeric based on their stability, and (3) they may be called as obligate or nonobligate [3]. A blend of these three pairs may develop a protein-protein interaction. For example, a permanent interaction of the protein may be able to form a stable protein complex while on the other hand a transient interaction among the proteins may form a signaling pathway [4].

To perform the function in a living cell, proteins rarely act as isolated species [5] instead over 80% of the proteins perform their functions in groups [6]. The function of an unidentified protein can be suggested by its interactions with a protein of known function. The thorough study of PPIs is also important to demonstrate the molecular mechanism of cellular processes of proteins [3]. The momentous properties of PPIs are (a) the kinetic properties of the enzymes can be modified by PPIs;(b) PPIs can allow substrate channeling;(c) they can create a new binding site for the small molecules;(d) PPIs can suppress or activate a protein;(e) PPIs can perform regulatory role in downstream or upstream regulation of the protein; and (f) they can also alter the specificity of binding of the protein for its particular substrate by changing its interactions [7].