The peptide chain of acetylphenylalanine-L-alaninephenylalanine-~ alanine methyl ester, C27H30N406, adopts a 3~0-helical conformation having tight-handed screw sense. The 310-helix is stabilized by intramolecular hydrogen bonds, between CO of the acetyl group and NH of APhe 3, and between CO of APhe I and NH of D-Ala 4. The hydrogen bonds form two consecutive tenmembered rings whose (% z/.,) torsion angles are quite close to the standard values for type-Ill/3-turns. In the crystal, the molecules are linked head-to-tail by intermolecular hydrogen bonds to form continuous helical columns. These are aligned along axes parallel to the c axis, with neighbouring columns running in opposite directions. There are no lateral hydrogen bonds between helical columns, but only hydrophobic interactions provided by the interdigitation of apolar side chains of the dehydro-phenylalanine residues, as well as of the Cterminal methyl ester groups.

Acetyl-APhe-L-Ala- APhe-l)-Ala MethylEster

TUZI, ANGELA;
1997

Abstract

The peptide chain of acetylphenylalanine-L-alaninephenylalanine-~ alanine methyl ester, C27H30N406, adopts a 3~0-helical conformation having tight-handed screw sense. The 310-helix is stabilized by intramolecular hydrogen bonds, between CO of the acetyl group and NH of APhe 3, and between CO of APhe I and NH of D-Ala 4. The hydrogen bonds form two consecutive tenmembered rings whose (% z/.,) torsion angles are quite close to the standard values for type-Ill/3-turns. In the crystal, the molecules are linked head-to-tail by intermolecular hydrogen bonds to form continuous helical columns. These are aligned along axes parallel to the c axis, with neighbouring columns running in opposite directions. There are no lateral hydrogen bonds between helical columns, but only hydrophobic interactions provided by the interdigitation of apolar side chains of the dehydro-phenylalanine residues, as well as of the Cterminal methyl ester groups.
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/11588/468917
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact