A crystal-state structural analysis of t-Boc-L-Ala-β-Ala-NHMe, t-Boc-Aib-β-Ala-NHMe, and t-Boc-Aib-Aib-β-Ala-NHMe has been performed by X-ray diffraction. While the conformation adopted by t-Boc-L-Ala-β-Ala- NHMe and t-Boc-Aib-β-Ala-NHMe is essentially extended, f-Boc-Aib-Aib- β-Ala-NHMe is folded into two consecutive intramolecularly hydrogen-bonded structures of the i + 3 → i type (β-bends), with Aib(1)-Aib(2) and Aib(2)-β-Ala(3), respectively, as corner residues. Owing to the presence of the β-aminoacid, the latter β-bend is characterized by an unusual C11 hydrogen-bonded ring. These results indicate that: (i) a β-aminoacid may be incorporated into a β-bend without a major perturbation of the overall geometry of this folded conformation, and (ii) the propensity of the β-Ala residue for β-bend formation is rather low, unless other conformational constraints (e.g. a preceding β-bend) are present in the linear peptide molecule.

BETA-ALANINE AND BETA-BENDS - X-RAY-DIFFRACTION STRUCTURES OF 3 LINEAR OLIGOPEPTIDES

ISERNIA, Carla;
1992

Abstract

A crystal-state structural analysis of t-Boc-L-Ala-β-Ala-NHMe, t-Boc-Aib-β-Ala-NHMe, and t-Boc-Aib-Aib-β-Ala-NHMe has been performed by X-ray diffraction. While the conformation adopted by t-Boc-L-Ala-β-Ala- NHMe and t-Boc-Aib-β-Ala-NHMe is essentially extended, f-Boc-Aib-Aib- β-Ala-NHMe is folded into two consecutive intramolecularly hydrogen-bonded structures of the i + 3 → i type (β-bends), with Aib(1)-Aib(2) and Aib(2)-β-Ala(3), respectively, as corner residues. Owing to the presence of the β-aminoacid, the latter β-bend is characterized by an unusual C11 hydrogen-bonded ring. These results indicate that: (i) a β-aminoacid may be incorporated into a β-bend without a major perturbation of the overall geometry of this folded conformation, and (ii) the propensity of the β-Ala residue for β-bend formation is rather low, unless other conformational constraints (e.g. a preceding β-bend) are present in the linear peptide molecule.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

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/11591/188870
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 41
  • ???jsp.display-item.citation.isi??? 38
social impact