[6] The WW domain is one of the smallest protein modules, composed of only 40 amino acids, which mediates specific protein-protein interactions with short proline-rich or proline-containing motifs.

[7] The identification of the WW domain was facilitated by the analysis of two splice isoforms of YAP gene product, named YAP1-1 and YAP1-2, which differed by the presence of an extra 38 amino acids.

[24] Recent study has shown that endohedral metallofullerenol, a compound that was originally developed as a contrasting agent for MRI (magnetic resonance imaging), has antineoplastic properties.

[26][27] Because of its small size and well-defined structure, the WW domain was developed by the Gruebele and Kelly groups into a favorite subject of protein folding studies.

[36][37] Ranganathan’s team has shown that a simple statistical energy function, which identifies co-evolution between amino acid residues within the WW domain, is necessary and sufficient to specify sequence that folds into native structure.

Based on these properties, WW domain has been shown to be a versatile platform for the chemical interrogation of intramolecular interactions and conformational propensities in folded proteins.