DELETIONS OF THE N-TERMINAL REGIONS OF THE HUMAN MELANOCORTIN RECEPTORS

The non-homologous N-terminal regions of four human melanocortin (MC) receptors were truncated in order to investigate their putative partic ipation in ligand binding, Eleven constructs were made, where differen t numbers of residues from the N terminus were deleted, These construc ts were used for transient expression experiments in COS cells and ana lysed by ligand binding. The results show that 27, 25, 28, and 20 amin o acids could be deleted from the N terminus of the human MC1, MC3, MC 4 and MC5 receptors, respectively, including all potential N-terminal glycosylation sites in the MC1 and the MC4 receptors, without affectin g ligand binding or expression levels, The results indicate that the N -terminal regions of the human MC1, MC3, MC4 and MC5 receptors, do not play an important role for the ligand binding properties of these rec eptors. (C) 1997 Federation of European Biochemical Societies.