Identification of Asn289 as a ligand binding site in the rat thyrotropin-releasing hormone (THR) receptor as determined by complementary modifications in the ligand and receptor: a new model for THR binding.

To test the hypothesis that pGlu of the thyrotropin-releasing hormone (TRH, pGlu-His-ProNH2) binds to Asn289 in the third extracellular loop (EL3) of its receptor through a hydrogen bonding interaction, we converted Asn289 to Asp (N289D mutant) and measured the potencies of TRH and Pro1TRH for the wild-type and mutant receptors. TRH was 100 times less… (More)