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Identification of the amino acid residues involved in selective agonist binding in the first extracellular loop of the δ‐ and μ‐opioid receptors
Author(s) -
Fukuda Kazuhiko,
Terasako Kiyoshi,
Kato Shigeshisa,
Mori Kenjiro
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01034-c
Subject(s) - receptor , agonist , lysine , asparagine , chemistry , amino acid , extracellular , biochemistry , peptide , stereochemistry
Effects of amino acid substitutions in the first extracellular loop region of the β‐ and μ‐opioid receptors were examined. Substitution of lysine‐108 of the δ‐receptor (δK108) with asparagine improved affinity to [ d ‐Ala 2 ,MePhe 4 ,Gly‐ol 5 ]enk ephalin (DAGO), a μ‐selective peptide agonist, to be comparable with that of the μ‐receptor. On the other hand, replacement of mN127 with lysine decreased the affinity to DAGO by ∼ 15‐fold. These results suggest that dK108 and mN127, which correspond to each other in the aligned amino acid sequences, mainly determine the difference in DAGO binding affinity between the δ‐ and μ‐receptors.