title: The effects of C-terminal modifications on the opioid activity of [N-benzylTyr(1)]dynorphin A-(1-11) analogues.
abstract: Structural modifications affecting the efficacy of analogues of the endogenous opioid peptide dynorphin (Dyn) A have focused on the N-terminal "message" sequence based on the "message-address" concept. To test the hypothesis that changes in the C-terminal "address" domain could affect efficacy, modified amino acids and cyclic constraints were incorporated into this region of the partial agonist [N-benzylTyr(1)]Dyn A-(1-11). Modifications in the C-terminal domain of [N-benzylTyr(1)]Dyn A-(1-11)NH(2) resulted in increased kappa opioid receptor (KOR) affinity for all of the linear analogues but did not affect the efficacy of these peptides at KOR. Cyclization between positions 5 and 8 yielded [N-benzylTyr(1),cyclo(d-Asp(5),Dap(8))]Dyn A-(1-11)NH(2) (zyklophin, 13) ( J. Med. Chem. 2005 , 48 , 4500 - 4503 ) with high selectivity for KOR. In contrast to the linear peptides, this peptide exhibits negligible efficacy in the adenylyl cyclase (AC) assay and is a KOR antagonist. These data are consistent with our hypothesis that appropriate modifications in the "address" domain of Dyn A analogues may affect efficacy.
authors.affiliation: Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
authors.forename: Kshitij A
authors.initials: KA
authors.lastname: Patkar
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Murray
authors.forename: Jane V
authors.initials: JV
authors.lastname: Aldrich
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004399:Dynorphins / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D008024:Ligands; D051379:Mice; D009842:Oligopeptides / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D010446:Peptide Fragments / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D017465:Receptors, Opioid, delta / Q000819:agonists; D017473:Receptors, Opioid, kappa / Q000819:agonists* / Q000037:antagonists & inhibitors; D017450:Receptors, Opioid, mu / Q000819:agonists; D013329:Structure-Activity Relationship
chemical_list: D008024:Ligands; D009842:Oligopeptides; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D017465:Receptors, Opioid, delta; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu; C502814:dynorphin A-(1-11)-NH2, Nalpha-benzylTyr(1)-cyclo(Asp(5)-Dap(8))-; D004399:Dynorphins; D000262:Adenylyl Cyclases