Combination of molecular modeling, site-directed mutagenesis, and SAR studies to delineate the binding site of pyridopyrimidine antagonists on the human CCK1 receptor.
A rational combination of site-directed mutagenesis studies, structure-activity relationships, and dynamic-based docking of pyridopyrimidine-derived CCK1R antagonists into a refined three-dimensional model of the CCK1R allowed us to identify the receptor residues and the ligand functional groups implicated in the molecular recognition process. Our results provided unambiguous evidence that the binding site of these antagonists is overlapping that of the C-terminal tetrapeptide of CCK. In particular, Asn333 and Arg336 residues of the CCK1R are essential for high-affinity binding of these ligands. Moreover, the 2-aryl group in the pyridopyrimidine derivatives shares the same binding pocket as the C-terminal Phe side chain of CCK. Our [pyridopyrimidine.CCK1R] complex model is consistent with previous suggestions concerning the molecular basis that governs functional activity and provides useful considerations about the high CCK1 versus CCK2 selectivity of our derivatives and could contribute to fine-tune the rational design of new molecules with optimized properties.
Martín-Martínez
Mercedes
M
Instituto de Química Médica (CSIC), Juan de la Cierva 3, E-28006 Madrid, Spain. iqmm317@iqm.csic.es
Marty
Anne
A
Jourdan
Maud
M
Escrieut
Chantal
C
Archer
Elodie
E
González-Muñiz
Rosario
R
García-López
M Teresa
MT
Maigret
Bernard
B
Herranz
Rosario
R
Fourmy
Daniel
D
D019943:Amino Acid Substitution; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D006801:Humans; D007295:Inositol Phosphates / Q000096:biosynthesis; D008024:Ligands; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011725:Pyridines / Q000737:chemistry* / Q000494:pharmacology; D011743:Pyrimidines / Q000737:chemistry* / Q000494:pharmacology; D011869:Radioligand Assay; D054389:Receptors, CCR1; D019707:Receptors, Chemokine / Q000037:antagonists & inhibitors* / Q000737:chemistry* / Q000235:genetics; D013329:Structure-Activity Relationship; D014162:Transfection
C515300:CCR1 protein, human; D007295:Inositol Phosphates; D008024:Ligands; D011725:Pyridines; D011743:Pyrimidines; D054389:Receptors, CCR1; D019707:Receptors, Chemokine