In the present paper we describe the synthesis, purification, single crystal x-ray analysis, and solution conformational characterization of the cyclic tetrapeptide cyclo- (L-Pro-beta-Ala-L-Pro-beta-Ala). This peptide was synthesized by classical solution methods and the cyclization of the free tetrapeptide was accomplished in good yields in diluted methylene chloride solution using N,N-dicyclohexyl-carbodiimide (DCCI). The compound crystallizes in the orthorombic space group P2(1)2(1)2(1) from ethyl acetate. All peptide bonds are trans. The molecular conformation is stabilized by two intramolecular hydrogen bonds between the CO and NH groups of the two beta-alanine residues. These hydrogen bonds take part in a C7 structure in which both proline residues occupy the 2 position of an inverse gamma-turn. The two beta-alanine residues have a typical folded conformation (around the C-alpha-C-beta-bond) observed in other cyclic peptides containing this residue. A detailed H-1-nmr analysis in CD3CN solution has been carried out. The molecule assumes a twofold symmetry in solution with a molecular conformation consistent with that observed in the solid state.

BETA-ALANINE CONTAINING PEPTIDES - A NOVEL MOLECULAR TOOL FOR THE DESIGN OF GAMMA-TURNS

PAVONE, VINCENZO;LOMBARDI, ANGELINA;D'AURIA, GABRIELLA;NASTRI, FLAVIA;
1992

Abstract

In the present paper we describe the synthesis, purification, single crystal x-ray analysis, and solution conformational characterization of the cyclic tetrapeptide cyclo- (L-Pro-beta-Ala-L-Pro-beta-Ala). This peptide was synthesized by classical solution methods and the cyclization of the free tetrapeptide was accomplished in good yields in diluted methylene chloride solution using N,N-dicyclohexyl-carbodiimide (DCCI). The compound crystallizes in the orthorombic space group P2(1)2(1)2(1) from ethyl acetate. All peptide bonds are trans. The molecular conformation is stabilized by two intramolecular hydrogen bonds between the CO and NH groups of the two beta-alanine residues. These hydrogen bonds take part in a C7 structure in which both proline residues occupy the 2 position of an inverse gamma-turn. The two beta-alanine residues have a typical folded conformation (around the C-alpha-C-beta-bond) observed in other cyclic peptides containing this residue. A detailed H-1-nmr analysis in CD3CN solution has been carried out. The molecule assumes a twofold symmetry in solution with a molecular conformation consistent with that observed in the solid state.
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/11588/404571
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 42
  • ???jsp.display-item.citation.isi??? 46
social impact