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β‐Alanine containing peptides: A novel molecular tool for the design of γ‐turns
Author(s) -
Pavone V.,
Lombardi A.,
D'auria G.,
Saviano M.,
Nastri F.,
Paolillo L,
Di Blasio B.,
Redone C.
Publication year - 1992
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360320207
Subject(s) - tetrapeptide , chemistry , hydrogen bond , residue (chemistry) , intramolecular force , peptide , alanine , stereochemistry , molecule , carbodiimide , cyclic peptide , peptide bond , salt bridge , methylene , guanidinium chloride , crystallography , amino acid , organic chemistry , biochemistry , mutant , gene , enzyme
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‐γ‐Ala‐ L ‐Pro‐γ‐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 β‐alanine residues. These hydrogen bonds take part in a C 7 structure in which both proline residues occupy the 2 position of an inverse γ‐turn. The two β‐alanine residues have a typical folded conformation (around the Cα‐Cβ bond) observed in other cyclic peptides containing this residue. A detailed 1 H‐nmr analysis in CD 3 CN 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.