Thecis-4-Amino-l-proline Residue as a Scaffold for the Synthesis of Cyclic and Linear Endomorphin-2 Analogues
摘要:
Endomorphin-2 (EM-2: Tyr-Pro-Phe-Phe-NH2) is an endogenous tetrapeptide that combines potency and efficacy with high affinity and selectivity toward the mu opioid receptor, the most responsible for analgesic effects in the central nervous system. The presence of the Pro(2) represents a crucial factor for the ligand structural and conformational properties. Praline is in fact an efficient stereochemical spacer, capable of inducing favorable spatial orientation of aromatic rings, a key factor for ligand recognition and interaction with receptors. Here the Pro(2) has been replaced by 4(S)-NH2-2(S)-proline (cAmp), a proline/GABA cis-chimera residue. This bivalent amino acid maintains the capacity to influenc the tetrapeptide conformation and offers the opportunity to generate new linear models and unusually constrained cyclic analogues characterized by an N-terminal Tyr bearing a free alpha-amino group. The results indicate that the new analogues do not show affinity for both delta and kappa opioid receptors and bind only poorly to the mu receptors (for cyclopeptide 9: K-i(mu) = 660 nM; GPI (IC50) = 1.4% at 1 mu M; for linear tetrapeptide acid 13: K-i(mu) = 2000 nM; GPI (IC50) = 0% at 1 mu M; for linear tetrapeptide amide 15: K-i(mu) = 310 nM; GPI (IC50) = 894 nM).
The<i>cis</i>-4-Amino-<scp>l</scp>-proline Residue as a Scaffold for the Synthesis of Cyclic and Linear Endomorphin-2 Analogues
作者:Adriano Mollica、Francesco Pinnen、Azzurra Stefanucci、Federica Feliciani、Cristina Campestre、Luisa Mannina、Anatoly P. Sobolev、Gino Lucente、Peg Davis、Josephine Lai、Shou-Wu Ma、Frank Porreca、Victor J. Hruby
DOI:10.1021/jm201402v
日期:2012.4.12
Endomorphin-2 (EM-2: Tyr-Pro-Phe-Phe-NH2) is an endogenous tetrapeptide that combines potency and efficacy with high affinity and selectivity toward the mu opioid receptor, the most responsible for analgesic effects in the central nervous system. The presence of the Pro(2) represents a crucial factor for the ligand structural and conformational properties. Praline is in fact an efficient stereochemical spacer, capable of inducing favorable spatial orientation of aromatic rings, a key factor for ligand recognition and interaction with receptors. Here the Pro(2) has been replaced by 4(S)-NH2-2(S)-proline (cAmp), a proline/GABA cis-chimera residue. This bivalent amino acid maintains the capacity to influenc the tetrapeptide conformation and offers the opportunity to generate new linear models and unusually constrained cyclic analogues characterized by an N-terminal Tyr bearing a free alpha-amino group. The results indicate that the new analogues do not show affinity for both delta and kappa opioid receptors and bind only poorly to the mu receptors (for cyclopeptide 9: K-i(mu) = 660 nM; GPI (IC50) = 1.4% at 1 mu M; for linear tetrapeptide acid 13: K-i(mu) = 2000 nM; GPI (IC50) = 0% at 1 mu M; for linear tetrapeptide amide 15: K-i(mu) = 310 nM; GPI (IC50) = 894 nM).