In Silico Study of Ligand Binding Site of Toll-Like Receptor 5

Background: Toll-like receptor-5 (TLR-5) is a member of TLRs family and responsible for bacterial flagellin recognition. The activation of TLR-5 with flagellin leads to initiation of signaling cascades, which in turn results in transcription of pro-inflammatory cytokines. Regarding the critical role of TLR-5 agonists and antagonists in activation of innate immune responses, an increasing number of studies have focused on their therapeutic applications in drug and vaccine design. In this study, to identify the most critical region and residues of TLR-5 for interaction with flagellin, different truncated forms of TLR-5 were designed and subjected to protein-protein interaction studies. Materials and Methods: The interactions of the full native TLR-5 and its truncated forms with bacterial flagellin (FliC) were evaluated using Hex docking server and molecular interaction analysis was performed using Dimplot analysis. Results: According to our in silico results, truncated form C (an amino acid sequence containing residues 174-401 of TLR-5) has the most suitable interaction with FliC and seven amino acids within this region were found to be crucial for the interaction with flagellin. Conclusions: These results provide new insights in to potential drug target sites of TLR-5, which may guide future TLR-5 targeting studies.