Interaction of theaflavin-3-gallate with heat-labile enterotoxin and Shiga toxin of Escherichia coli: In silico analysis

Bioactive compounds, specifically polyphenols have illustrated biocompatible and therapeutic properties. Finding specific targets of these metabolites is a vital affair in pharmaceutical technology. Theaflavin-3-gallate extracted from black tea has exhibited sporicidal, antiplanktonic, and antibiofilm activities against both Gram-negative and Gram-positive bacteria. In the case of Escherichia coli as Gram-negative bacteria, we used the CB-Dock2 server and AutoDock Vina software for the assessment of the interaction of theaflavin-3-gallate with Shiga toxin and heat-labile enterotoxin as major virulence factors. Additionally, protein-protein interactions of these virulence factors have been determined by the STRING database. This in silico study resulted in both AutoDock Vina and CB-Dock2 exhibited the lower binding energy for interaction of theaflavin-3-gallate metabolite with Shiga toxin type 2a receptor compared with the heat-labile enterotoxin type IIB receptor. Based on the results of the STRING database, a higher score related to the Shiga-like toxin II B subunit is predicted as the important functional protein, which Shiga toxin type 2a may interact with this subunit.