Abstract:
Among the various treatments, glp-1 receptor agonists (incretin mimics) such as liraglutide and exenatide have been well received in treating type 2 diabetes mellitus (t2dm) and obesity. In this study, an exenatide analogue, in which methionine at position 14 substituted with leucine, was ligated to human αb-crystallin (αb-cry) and then expressed in the bacterial host cells. In the next step, the exenatide analogue was effectively released from the hybrid protein (αb-ex) and subsequently purified using gel filtration chromatography. The hplc and electrospray ionization mass spectrometry (esi-ms) analyses respectively suggested a high purity (more than 97%) and an accurate molecular mass for the exenatide analogue (4168.22 da and 835.01, z = 5). Also, the molecular mass of the αb-ex hybrid protein based on the maldi-tof analysis was 24,702.162 da. The secondary structure assessment by the three spectroscopic methods revealed that exenatide analogue and αb-ex hybrid protein have an α-helix and a β-sheet rich structure, respectively. Also, according to the results of the dls analysis, the αb-ex hybrid protein indicated a high tendency to form large oligomeric structures. The nmr assessment suggested that the hybrid protein exists in its folding state. Both exenatide analogue and the αb-ex hybrid protein revealed a crucial ability to reduce the blood sugar levels in healthy and diabetic mice. They were also capable of inducing insulin secretion to the bloodstream. Overall, our study introduces the αb-ex hybrid protein as a novel incretin mimic, exerting its biological activity for a longer period of time. It might also be considered a potential drug candidate in the treatment of t2dm. © 2022