A series of N- and C-protected, monodispersed homo-oligopeptides (to the pentamer level) from the cycloaliphatic C-alpha,C-alpha-dialkylated glycine 1-aminocyclononane-1-carboxylic acid (Ac(9)c) and two Ala/Ac(9)c tripeptides have been synthesized by solution methods and fully characterized. The conformational preferences of all the model peptides were determined in deuterochloroform solution by FT-IR absorption and H-1-NMR. The molecular structures of the amino acid derivatives mClAc-Ac(9)c-OH and Z-Ac(9)c-OtBu, the dipeptide pBrBz-(Ac(9)c)(2)-OtBu, the tetrapeptide Z-(Ac(9)c)(4)-OtBu, and the pentapeptide Z-(Ac(9)c)(5)-OtBu were determined in the crystal state by X-ray diffraction. Based on this information, the average geometry and the preferred conformation for the cyclononyl moiety of the Ac(9)c residue have been assessed. The backbone conformational data are strongly in favour of the conclusion that the Ac(9)c residue is a strong beta-turn and helix former. A comparison with the structural propensity of alpha-aminoisobutyric acid, the prototype of C-alpha,C-alpha-dialkylated glycines, and the other extensively investigated members of the family of 1-aminocycloalkane-1-carboxylic acids (Ac(n)c, with n=3-8) is made and the implications for the use of the Ac(9)c residue in conformationally constrained analogues of bioactive peptides are briefly examined. (C) European Peptide Society and John Wiley & Sons, Ltd.

Conformational characterization of peptides rich in the cycloaliphatic C-alpha,C-alpha-disubstituted glycine 1-aminocyclononane-1-carboxylic acid

FORMAGGIO, FERNANDO;TONIOLO, CLAUDIO;
1997

Abstract

A series of N- and C-protected, monodispersed homo-oligopeptides (to the pentamer level) from the cycloaliphatic C-alpha,C-alpha-dialkylated glycine 1-aminocyclononane-1-carboxylic acid (Ac(9)c) and two Ala/Ac(9)c tripeptides have been synthesized by solution methods and fully characterized. The conformational preferences of all the model peptides were determined in deuterochloroform solution by FT-IR absorption and H-1-NMR. The molecular structures of the amino acid derivatives mClAc-Ac(9)c-OH and Z-Ac(9)c-OtBu, the dipeptide pBrBz-(Ac(9)c)(2)-OtBu, the tetrapeptide Z-(Ac(9)c)(4)-OtBu, and the pentapeptide Z-(Ac(9)c)(5)-OtBu were determined in the crystal state by X-ray diffraction. Based on this information, the average geometry and the preferred conformation for the cyclononyl moiety of the Ac(9)c residue have been assessed. The backbone conformational data are strongly in favour of the conclusion that the Ac(9)c residue is a strong beta-turn and helix former. A comparison with the structural propensity of alpha-aminoisobutyric acid, the prototype of C-alpha,C-alpha-dialkylated glycines, and the other extensively investigated members of the family of 1-aminocycloalkane-1-carboxylic acids (Ac(n)c, with n=3-8) is made and the implications for the use of the Ac(9)c residue in conformationally constrained analogues of bioactive peptides are briefly examined. (C) European Peptide Society and John Wiley & Sons, Ltd.
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2523545
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 14
social impact