Glucagon-like peptide-1 (GLP-1) possesses multiple physiological functions, which make it a potential drug candidate for the treatment of type 2 diabetes. However, its clinical application was limited severely by its short half-life in vivo. Therefore, stabilization of GLP-1 is critical for the use of this peptide in drug development. In this study, a novel GLP-1 derivative, VGLP1K6, processed a significantly prolonged half-life in vivo. Structural analysis using molecular dynamics simulations demonstrated that VGLP1K6 has a rigid V-shaped conformation resulting from the intrapeptide disulfide bond. The C-terminal polylysine residues of VGLP1K6 caused the vulnerable N-terminus of GLP-1 (HA-fragment) to reside within the pocket-like cavity of the peptide due to the intrahydrogen bonds. The structural analysis suggested that this structural alteration contributed to the remarkable prolonged half-life of VGLP1K6, which was approximately 70 h. In addition, VGLP1K6 induced better long-acting glucose tolerance and greater HbA1c reductions than GLP-1 in rodents. Our findings suggest that the GLP-1 derivative VGLP1K6 might be a possible potent antidiabetic drug for the treatment of type 2 diabetes mellitus.
Keywords: GLP-1 analogues; HbA1c; cAMP; glucose tolerance test; insulin stimulation; long-acting GLP-1.