“…Thus, receptor binding must depend principally on the maintenance of the structure of the C-terminal helix 22-34 and the availability of Structure of PTHrP [Ala 15 ]- a binding interface within this segment. The structure of the C-terminal helix is maintained even without the hydrophobic interactions found in several other studies, in particular those between residues 15 and 23 in both PTH (16,21) and PTHrP (13,15,18,20). Other interactions, besides the formation of a hydrophobic core, act to stabilize the C-terminal helix.…”