1. Academic Validation
  2. Structure-activity relationships of human urotensin II and related analogues on rat aortic ring contraction

Structure-activity relationships of human urotensin II and related analogues on rat aortic ring contraction

  • J Enzyme Inhib Med Chem. 2003 Apr;18(2):77-88. doi: 10.1080/1475636031000093507.
Patricia Labarrère 1 David Chatenet Jérôme Leprince Céline Marionneau Gervaise Loirand Marie-Christine Tonon Christophe Dubessy Elizabeth Scalbert Bruno Pfeiffer Pierre Renard Bernard Calas Pierre Pacaud Hubert Vaudry
Affiliations

Affiliation

  • 1 Centre de Biochimie Structurale, CNRS UMR 5048, INSERM UMR 554, Université de Montpellier 1, 34090 Montpellier, France.
Abstract

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.

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