title: Novel synthesis of cyclic amide-linked analogues of angiotensins II and III.
abstract: Cyclic amide-linked angiotension II (ANGII) analogues have been synthesized by novel strategies, in an attempt to test the ring clustering and the charge relay bioactive conformation recently suggested. These analogues were synthesized by connecting side chain amino and carboxyl groups at positions 1 and 8, 2 and 8, 3 and 8, and 3 and 5, N-terminal amino and C-terminal carboxyl groups at positions 1 and 8, 2 and 8, and 4 and 8, and side chain amino to C-terminal carboxyl group at positions 1 and 8. All these analogues were biologically inactive, except for cyclic [Sar1, Asp3, Lys5]ANGII (analogue 10) which had high contractile activity in the rat uterus assay (30% of ANGII) and [Lys1, Tyr(Me)4, Glu8]ANGII (analogue 7) which had weak antagonist activity (PA2 approximately 6). Precyclic linear peptides synthesized using 2-chlorotrityl chloride resin and N alpha-Fmoc-amino acids with suitable side chain protection were obtained in high yield and purity and were readily cyclized with benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate as coupling reagent. Molecular modeling suggests that the ring structure of the potent analogue can be accommodated in the charge relay conformation proposed for ANGII.
authors.affiliation: Department of Chemistry, University of Patras, Greece.
authors.forename: J M
authors.initials: JM
authors.lastname: Matsoukas
authors.forename: J
authors.initials: J
authors.lastname: Hondrelis
authors.forename: G
authors.initials: G
authors.lastname: Agelis
authors.forename: K
authors.initials: K
authors.lastname: Barlos
authors.forename: D
authors.initials: D
authors.lastname: Gatos
authors.forename: R
authors.initials: R
authors.lastname: Ganter
authors.forename: D
authors.initials: D
authors.lastname: Moore
authors.forename: G J
authors.initials: GJ
authors.lastname: Moore
mesh_terms: D000595:Amino Acid Sequence; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D000805:Angiotensin III / Q000031:analogs & derivatives / Q000138:chemical synthesis; D000818:Animals; D003500:Cyclization; D005260:Female; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D010456:Peptides, Cyclic / Q000138:chemical synthesis* / Q000494:pharmacology; D011487:Protein Conformation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013329:Structure-Activity Relationship; D014590:Uterine Contraction / Q000187:drug effects
chemical_list: D010456:Peptides, Cyclic; D000804:Angiotensin II; D000805:Angiotensin III