Design, Expression, and Binding Interactions Study of the Recombinant Engineered IL-6R

Abstract

Background: The trans-signaling pathway mediated by soluble interleukin-6 receptor (IL-6R) plays a crucial role in the pathogenesis of chronic inflammatory diseases, autoimmune disorders, and various cancers. Objectives: The present study aimed to model amino acid residues 121 to 300 of the IL-6R and to predict the effect of this selected fragment on reducing its interaction with glycoprotein 130 (gp130) using molecular docking. Methods: The engineered selected sequence interleukin-6 receptor (seIL-6R) was designed to diminish interaction with gp130. Physicochemical parameters were evaluated using the ProtParam tool. Structural modeling and prediction were performed using AlphaFold. Molecular docking was conducted using ClusPro. Subsequently, the seIL-6R gene was recombinantly expressed in the Chinese hamster ovary (CHO)-K1 cell line. The expression of recombinant seIL-6R was evaluated by Western blotting, and its secondary structure was examined by Fourier transform infrared (FTIR) spectroscopy. Results: Evaluation of the physicochemical parameters of the recombinant seIL-6R protein demonstrated improved stability and solubility, along with a reduced molecular weight (20.6 kDa). Molecular docking results indicated reduced binding of seIL-6R to gp130. Expression of the recombinant seIL-6R protein was confirmed by Western blotting. Furthermore, FTIR spectroscopy revealed that the secondary structure of seIL-6R was preserved and consistent with predicted structural models. Conclusions: This engineered protein has potential for further investigation as a promising and cost-effective therapeutic agent targeting IL-6-related pathologies.