Glucagon, conformational studies

Monomeric glucagon in aqueous solution was studied by nuclear magnetic resonance (NMR). These studies confirmed earlier observations that monomeric glucagon in aqueous solution adopts a predominantly flexible random coil form and further revealed a structured region involving the residues - Phe 22 - Val 23 -Gin 24 - Trp 25 -, with a conformation different from an a-helix-type secondary structure [9]. 

The development of a glucagon antagonist which lowers blood glucose levels in diabetic animals [66] illustrates the importance of careful binding studies in conjunction with full dose-response analysis of activity. In addition these studies provide another illustration of the manner in which steric changes which cause conformational perturbations apparently can lead to antagonist analogs. 

---