Molecular docking predicting the C-phycocyanin role on pro-apoptotic proteins

Bax and p53 proteins are interesting therapeutic targets, as they signal apoptosis and prevent neoplasms. In most cancers, these proteins are downregulated to support tumor survival. A C-phycpcyanin (C-PC) is a phycobiliprotein with diverse biological activities and could upregulate Bax and P53 in tumor cells. To assess the interaction between C-PC and pro-apoptotic proteins, docking is a valuable screening tool avoiding time and resources spent on in vitro experiments if this interaction does not occur in silico. Using PRISM web server (algorithm based on structural matching) the interaction of the C-PC (PDB ID: 1GH0) was verified in its complete form (Full) or just its F chain with two proapoptotic proteins (p53- PDB ID: 1C26- and Bax- PDB ID: 1F16). The C-PC does not interact with p53, only Bax in its two forms with binding energy of -1.54 (Full) and -21.97 (chain F). UCSF Chimera (program for the interactive visualization and analysis of molecular structures) revealed that the F chain was connected to Bax by two Hydrogen bonds and 180 varied connections (polar, nonpolar, favorable and unfavorable). In silico analyzes showed preferential interaction of C-PC with Bax, without any interaction with p53. The higher binding energy with the F chain in relation to the complete structure of C-PC indicates greater stability of the protein complex. The docking demonstrated the feasibility of carrying out in vitro and in vivo studies to assess the possible stimulatory role of C-PC on Bax.