Biophysics and Physicobiology
Online ISSN : 2189-4779
ISSN-L : 2189-4779
Regular Article
Specificity of broad protein interaction surfaces for proteins with multiple binding partners
Nobuyuki UchikogaYuri MatsuzakiMasahito OhueYutaka Akiyama
Author information

2016 Volume 13 Pages 105-115


Analysis of protein-protein interaction networks has revealed the presence of proteins with multiple inter­action ligand proteins, such as hub proteins. For such proteins, multiple ligands would be predicted as interacting partners when predicting all-to-all protein-protein interactions (PPIs). In this work, to obtain a better understanding of PPI mechanisms, we focused on protein interaction surfaces, which differ between protein pairs. We then performed rigid-body docking to obtain information of interfaces of a set of decoy structures, which include many possible interaction surfaces between a certain protein pair. Then, we investigated the specificity of sets of decoy interactions between true binding partners in each case of alpha-chymotrypsin, actin, and cyclin-dependent kinase 2 as test proteins having mul­tiple true binding partners. To observe differences in interaction surfaces of docking decoys, we introduced broad interaction profiles (BIPs), generated by assembling interaction profiles of decoys for each protein pair. After cluster analysis, the specificity of BIPs of true binding partners was observed for each receptor. We used two types of BIPs: those involved in amino acid sequences (BIP-seqs) and those involved in the compositions of interacting amino acid residue pairs (BIP-AAs). The specificity of a BIP was defined as the number of group members including all true binding partners. We found that BIP-AA cases were more specific than BIP-seq cases. These results indicated that the composition of inter­acting amino acid residue pairs was sufficient for determining the properties of protein interaction surfaces.

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