EFFECT OF TOLL-LIKE RECEPTOR INHIBITOR IMIQUIMOD ON IL1R1 INTERACTION WITH IL-1RA AND ITS SNP VARIANT-AN IN SILICO APPROACH

Objective: Interleukin 1 receptor antagonist (IL1Ra) acts as an antagonist to Interleukin 1 beta (IL1β) signalling in maintaining homeostasis. A loss of function due to Single Nucleotide Polymorphism (SNP) occurrence in IL1Ra can lead to dysregulated state as seen in autoimmune disease pathogenesis. The current study aims at achieving conformational stability in the IL1R1-IL1Ra_SNP complex by introducing a ligand into the region apart from the active site of Interleukin 1 receptor type1 (IL1R1).Methods: Protein-protein docking was performed using ClusPro, for IL1R1 with IL1β, IL1Ra and IL1Ra_SNP variant to study the difference in the interaction between the complexes. A known inhibitor, Imiquimod was docked using Glide, to the Il1R1-IL1Ra_SNP complex using flexible docking and the change in surface energy was calculated.Results: Binding Interactions show that IL1Ra binds more avidly to IL1R1 than IL1β. Conformational instability was seen in the IL1R1-IL1Ra_SNP complex. The difference in the amino acid interactions between the IL1R1 with IL1Ra and IL1Ra_SNP variant further illustrated the change in binding residues and hydrogen bond formation. Upon docking of an appropriate ligand to the IL1R1-IL1Ra_SNP complex, the conformational stability of the IL1R1-IL1Ra_SNP complex enhanced considerably suggesting a possible mechanism for treating SNP-induced conformational instability.Conclusion: Toll-like receptors like IL1R1 have many binding pockets apart from its active site. No strategies have yet been reported in targeting them for correcting conformational instability induced by SNP. Through our study, it was observed that the conformational instability of IL1R1-IL1Ra_SNP complex decreased upon introducing an appropriate small molecule.Keywords: IL1β, IL1R1, IL1Ra, SN