title: Identification of a critical aspartate residue in transmembrane domain three necessary for the binding of somatostatin to the somatostatin receptor SSTR2.
abstract: To determine which residues within the rat somatostatin receptor subtype SSTR2 may be interacting with the lys9 of somatostatin-14 (S-14), mutant SSTR2 receptors were created by mutating asp89 or asp122. [125I Tyr11]S-14 binding to D89A and D89E mutants suggests that asp89 is not directly involved in S-14 binding. Binding studies with the charge switch mutants, asp9S-14, and D122K, suggest that asp122 may be interacting with the lys9 of S-14. [125I Tyr11]asp9S-14 displayed saturable binding to D122K with an affinity comparable to that seen with [125I Tyr11]S-14 and WT SSTR2. These data suggest that the interaction between lys9 of S-14 and the TM3 asp122 of SSTR2 represents one contact site between S-14 and SSTR2.
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000032:analysis* / Q000378:metabolism; D001665:Binding Sites; D001667:Binding, Competitive; D016466:CHO Cells; D002462:Cell Membrane / Q000737:chemistry*; D006224:Cricetinae; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000494:pharmacology; D006727:Hormone Antagonists / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D010456:Peptides, Cyclic / Q000378:metabolism; D051381:Rats; D017481:Receptors, Somatostatin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013004:Somatostatin / Q000378:metabolism*; D013329:Structure-Activity Relationship; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism
chemical_list: D006727:Hormone Antagonists; D010456:Peptides, Cyclic; D017481:Receptors, Somatostatin; D001224:Aspartic Acid; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D014443:Tyrosine; D013004:Somatostatin; C040968:seglitide