Biomaterial Database

Identification of specific regions of the human endothelin-B receptor required for high affinity binding with endothelin-3. 1994

M Adachi, and Y Furuichi, and C Miyamoto

Department of Molecular Genetics, Nippon Roche Research Center, Kanagawa pref., Japan.

To investigate the endothelin-3 (ET-3) binding region of the endothelin-B (ETB) receptor, we have transiently produced various chimeric endothelin receptors in transfected Chinese hamster ovary cells. Using 125I-ET-1 as the radioactive ligand in the displacement experiment, the replacement of both the second and third extracellular regions including the flanking transmembranes of the ETB receptor with the corresponding domains of the endothelin-A (ETA) receptor, increased the apparent Ki value for ET-3 from 5 x 10(-11) M to 10(-8) M. The affinity of this chimeric receptor, ETB-BC, for ET-3 was about two orders lower than ETB yet one order higher than ETA. Previously we have reported the involvement of Lys-140 located in the C-terminus of the second transmembrane region of the ETA receptor for ET-1 binding (Eur. J. Biochem., 220, 37-43, 1994). To assess the importance of the corresponding Lys-161 of the ETB receptor in ET-3 binding, we have replaced it with Ile in the ETB receptor. The mutant receptor had a 5.6-fold reduction in its affinity for ET-3, but its affinity for ET-1 remained similar. These results demonstrate that Lys-161 of the receptor is important for high affinity binding with ET-3 which, in part, confers the non-selective binding characteristics of the ETB receptor for ET isopeptides.

UI	MeSH Term	Description	Entries
D007457	Iodine Radioisotopes	Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes.	Radioisotopes, Iodine
D008239	Lysine	An essential amino acid. It is often added to animal feed.	Enisyl,L-Lysine,Lysine Acetate,Lysine Hydrochloride,Acetate, Lysine,L Lysine
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D001667	Binding, Competitive	The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.	Competitive Binding
D016232	Endothelins	21-Amino-acid peptides produced by vascular endothelial cells and functioning as potent vasoconstrictors. The endothelin family consists of three members, ENDOTHELIN-1; ENDOTHELIN-2; and ENDOTHELIN-3. All three peptides contain 21 amino acids, but vary in amino acid composition. The three peptides produce vasoconstrictor and pressor responses in various parts of the body. However, the quantitative profiles of the pharmacological activities are considerably different among the three isopeptides.	Endothelium-Derived Vasoconstrictor Factors,Endothelin,Vasoconstrictor Factors, Endothelium-Derived
D016466	CHO Cells	CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.	CHO Cell,Cell, CHO,Cells, CHO