title: Solution structure of a novel ETB receptor selective agonist ET1-21 [Cys(Acm)1,15, Aib3,11, Leu7] by nuclear magnetic resonance spectroscopy and molecular modelling.
abstract: The solution structure of a biologically active modified linear endothelin-1 analogue, ET1-21[Cys(Acm)1,15, Aib3,11, Leu7], has been determined for the first time by two-dimensional nuclear magnetic resonance spectroscopy in a methanol-d3/water solvent mixture. Out of approximately one hundred linear peptide analogues tested by biological assay, this peptide, together with a dozen others, showed significant ETB selective agonist activity. Here we report the solution structure of an ETB selective agonist of a full-length, synthetic linear endothelin analogue. The calculated structures indicate that the peptide adopts an alpha-helical conformation between residues Ser5-His16, whilst both N- and C-termini show no preferred conformation. These results suggest that the disulphide bridges normally associated with endothelin and sarafotoxin peptides may not necessarily be important for either ETB receptor binding activity or the formation of a helical conformation in solution.
authors.affiliation: Department of Chemistry, University of Edinburgh, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Hewage
authors.forename: L
authors.initials: L
authors.lastname: Jiang
authors.forename: J A
authors.initials: JA
authors.lastname: Parkinson
authors.forename: R
authors.initials: R
authors.lastname: Ramage
authors.forename: I H
authors.initials: IH
authors.lastname: Sadler
mesh_terms: D019332:Endothelin-1 / Q000031:analogs & derivatives* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010452:Peptide Biosynthesis; D010446:Peptide Fragments / Q000737:chemistry*; D010455:Peptides; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid
chemical_list: D019332:Endothelin-1; D010446:Peptide Fragments; D010455:Peptides; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; C119962:endothelin-1 (1-21), (Cys,Acm(1,15),Aib(3,11),Leu(7))-