Determination of the binding mode of thienopyrimidinedione antagonists to the human gonadotropin releasing hormone receptor using structure-activity relationships, site-directed mutagenesis, and homology modeling.
We have investigated the specific interactions of a series thienopyrimidinediones with the gonadotropin-releasing hormone receptor (GnRH-R). Competitive radioligand binding assays were used to determine the effect of several mutants on nonpeptide binding. Distinct interactions were observed in two separate regions: the N-terminal end of TM7 and the C-terminal end of TM6. The effects of mutants at D302((7.32)) and H306((7.36)) suggest that these residues are part of a hydrogen-bond network important for anchoring the nonpeptides. Structure-activity relationships indicated urea substituents on the 6-(4-aminophenyl) group with a trans conformational preference bind with high affinity and are sensitive to D302((7.32)) mutations. Another interaction area was found between the N-benzyl-N-methylamino substituent and L300((6.68)) and Y290((6.58)). These interaction sites facilitated the derivation of a model in which a representative member of the series was docked into GnRH-R. The model is consistent with known SAR and illuminates inconsistencies with previous hypotheses regarding how this series interacts with the receptor.
Betz
Stephen F
SF
Department of Endocrinology, Neurocrine Biosciences, Inc., 12790 El Camino Real, San Diego, California 92130, USA. sbetz@neurocrine.com
Lio
Francisco M
FM
Gao
Yinghong
Y
Reinhart
Greg J
GJ
Guo
Zhiqiang
Z
Mesleh
Michael F
MF
Zhu
Yun-Fei
YF
Struthers
R Scott
RS
D000595:Amino Acid Sequence; D000818:Animals; D001667:Binding, Competitive; D019556:COS Cells; D002522:Chlorocebus aethiops; D006801:Humans; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D017433:Protein Structure, Secondary; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011869:Radioligand Assay; D011966:Receptors, LHRH / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship; D013876:Thiophenes / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology
D008024:Ligands; D011743:Pyrimidines; D011966:Receptors, LHRH; D013876:Thiophenes