HUMAN NEUROPEPTIDE Y1 RECEPTOR EXPRESSED IN ESCHERICHIA-COLI RETAINS ITS PHARMACOLOGICAL PROPERTIES

The coding region of the gene for the human neuropeptide Y (NPY) Y1 re ceptor was fused to the maltose binding protein gene, Expression of th is transcription unit, after derepression with isopropyl beta-D-thioga lactopyranoside, was evidenced by the appearance of a protein of highe r molecular weight, as well as the native maltose binding protein, bot h of which were inmunoreactive with anti-maltose binding protein antib odies, Specific [I-125]Npy binding activity was found associated mainl y with the inner bacterial membrane fraction, suggesting that the rece ptor is correctly folded in this membrane. Competition binding experim ents using NPY Y1- and Y2-specific ligands clearly exhibited a NPY Y1 specific pharmacological profile with K-d values indistinguishable fro m those of the native receptor. These results suggest that the membran e environment required by the human NPY Y1 receptor for specific high- affinity ligand binding is conserved in this heterologous bacterial sy stem and can be used for detailed analyses of ligand-receptor interact ion and drug screening.