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Conformational characterization of peptides rich in the cycloaliphatic C α,α ‐disubstituted glycine 1‐amino‐cyclononane‐1‐carboxylic acid
Author(s) -
Gatos Maddalena,
Formaggio Fernando,
Crisma Marco,
Valle Giovanni,
Toniolo Claudio,
Bonora Gian Maria,
Saviano Michele,
Iacovino Rosa,
Menchise Valeria,
Galdiero Stefania,
Pedone Carlo,
Benedetti Ettore
Publication year - 1997
Publication title -
journal of peptide science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 66
eISSN - 1099-1387
pISSN - 1075-2617
DOI - 10.1002/(sici)1099-1387(199709)3:5<367::aid-psc116>3.0.co;2-v
Subject(s) - chemistry , tripeptide , tetrapeptide , dipeptide , residue (chemistry) , stereochemistry , pentapeptide repeat , pentamer , aminoisobutyric acid , moiety , peptide conformation , peptide , carboxylic acid , amino acid , oligopeptide , organic chemistry , biochemistry
A series of N‐ and C‐protected, monodispersed homo‐oligopeptides (to the pentamer level) from the cycloaliphatic C α,α, ‐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 1 H‐NMR. The molecular structures of the amino acid derivatives mClAc‐Ac 9 c‐OH and Z‐Ac 9 c‐OtBu, the dipeptide p BrBz‐(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 β‐turn and helix former. A comparison with the structural propensity of α‐aminoisobutyric acid, the prototype of C α,α ‐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. © 1997 European Peptide Society and John Wiley & Sons, Ltd. J. Pep. Sci. 3: 367–382 No. of Figures: 10. No. of Tables: 6. No. of References: 62