Structure-activity relationships of human urotensin II and related analogues on rat aortic ring contraction.
The sequence of human urotensin II (UII) has been recently established as H-Glu-Thr-Pro-Asp-Cys-Phe-Trp-Lys-Tyr-Cys-Val-OH, and it has been reported that UII is the most potent mammalian vasoconstrictor peptide identified so far. A series of UII analogues was synthesized, and the contractile activity of each compound was studied in vitro using de-endothelialised rat aortic rings. Replacement of each amino acid by an L-alanine or by a D-isomer showed that the N- and C-terminal residues flanking the cyclic region of the amidated peptide were relatively tolerant to substitution. Conversely, replacement of any residue of the cyclic region significantly reduced the contractile activity of the molecule. The octapeptide UII(4-11) was 4 times more potent than UII, indicating that the C-terminal region of the molecule possesses full biological activity. Alanine or D-isomer substitutions in UII(4-11) or in UII(4-11)-NH2, respectively, showed a good correlation with the results obtained for UII-NH2. Disulfide bridge disruption or replacement of the cysteine residues by their D-enantiomers markedly reduced the vasoconstrictor effect of UII and its analogues. In contrast, acetylation of the N-terminal residue of UII and UII-NH2 enhanced the potency of the peptide. Finally, monoiodination of the Tyr6 residue in UII(4-11) increased by 5 fold the potency of the peptide in the aortic ring bioassay. This structure-activity relationship study should provide useful information for the rational design of selective and potent UII receptor agonists and antagonists.
Labarrère
Patricia
P
Centre de Biochimie Structurale, CNRS UMR 5048, INSERM UMR 554, Université de Montpellier 1, 34090 Montpellier, France.
Chatenet
David
D
Leprince
Jérôme
J
Marionneau
Céline
C
Loirand
Gervaise
G
Tonon
Marie-Christine
MC
Dubessy
Christophe
C
Scalbert
Elizabeth
E
Pfeiffer
Bruno
B
Renard
Pierre
P
Calas
Bernard
B
Pacaud
Pierre
P
Vaudry
Hubert
H
D000595:Amino Acid Sequence; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D013329:Structure-Activity Relationship; D014579:Urotensins / Q000737:chemistry / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000737:chemistry / Q000494:pharmacology
D010446:Peptide Fragments; D014579:Urotensins; D014662:Vasoconstrictor Agents; C029677:urotensin II