Expression, purification and molecular dynamics simulation of extracellular domain of glucagon-like peptide-2 receptor linked to teduglutide.

Teduglutide is the only drug approved for long-term treatment of short bowel syndrome (SBS). This drug exerts its pharmacological effects via binding to the GLP-2 receptors (ECD-GLP2R) located in intestinal tissue. The three dimensional (3D) structure of ECD-GLP2R hasn't been determined yet and hence its mode of interaction with agonists/antagonists is not clear. Therefore, it would be of great importance to develop a structural scaffold for investigation of ECD-GLP2R interactions with its binders. For this, the current study aimed to produce fusion protein of ECD-GLP2R-teduglutide. The ECD-GLP2R-teduglutide protein was expressed in bacterial expression system and purified using affinity and size exclusion chromatography techniques. Using circular dichroism the secondary structure content of purified protein was determined which was comparable to that of theoretical calculations. The low structural stability of purified protein (ΔG = 3.64 kJ.mol) was elucidated by monitoring its fluorescence emission at the presence of various concentrations of GdnHCl as a denaturant. Finally, a 3D model for ECD-GLP2R-teduglutide protein was generated and validated using molecular dynamics simulation whose information alongside the experimental studies can be useful for providing new insight into the mode of interaction of ECD-GLP2R with its specific ligands in order to design potent and specific GLP2R agonists.