title: Further studies of tyrosine surrogates in opioid receptor peptide ligands.
abstract: A series of opioid peptide ligands containing modified N-terminal tyrosine (Tyr) residues was prepared and evaluated against cloned human mu, delta, and kappa opioid receptors. This work extends the recent discovery that (S)-4-carboxamidophenylalanine (Cpa) is an effective tyrosine bioisostere. Amino acids containing negatively charged functional groups in place of tyrosine's phenolic hydroxyl lacked receptor affinity, while exchange of Tyr for (S)-4-aminophenylalanine was modestly successful. Peptides containing the new amino acids, (S)-4-carboxamido-2,6-dimethylphenylalanine (Cdp) and (S)-beta-(2-aminobenzo[d]thiazol-6-yl)alanine (Aba), displayed binding (K(i)) and functional (EC(50)) profiles comparable to the parent ligands at the three receptors. Cdp represents the best performing Tyr surrogate in terms of overall activity, while Cpa and Aba show a subtle proclivity toward the delta receptor.
authors.affiliation: Department of Chemistry, Adolor Corporation, 700 Pennsylvania Drive, Exton, PA 19341, USA. rdolle@adolor.com
authors.forename: Roland E
authors.initials: RE
authors.lastname: Dolle
authors.forename: Mathieu
authors.initials: M
authors.lastname: Michaut
authors.forename: Blanca
authors.initials: B
authors.lastname: Martinez-Teipel
authors.forename: Serge
authors.initials: S
authors.lastname: Belanger
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Graczyk
authors.forename: Robert N
authors.initials: RN
authors.lastname: DeHaven
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D003001:Cloning, Molecular; D015195:Drug Design; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D008024:Ligands; D008956:Models, Chemical; D008968:Molecular Conformation; D010455:Peptides / Q000737:chemistry*; D011957:Receptors, Opioid / Q000737:chemistry*; D017465:Receptors, Opioid, delta / Q000737:chemistry; D017473:Receptors, Opioid, kappa / Q000737:chemistry; D017450:Receptors, Opioid, mu / Q000737:chemistry; D014443:Tyrosine / Q000737:chemistry*
chemical_list: D008024:Ligands; D010455:Peptides; D011957:Receptors, Opioid; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; D014443:Tyrosine