New tools for the control of peptide conformation: the helicogenic Calpha-methyl, Calpha-cyclohexylglycine

J Pept Res. 2004 Feb;63(2):161-70. doi: 10.1111/j.1399-3011.2003.00123.x.

Abstract

The novel Calpha-tetrasubstituted alpha-amino acid Calpha-methyl, Calpha-cyclohexylglycine was prepared by hydrogenation of its Calpha-methyl, Calpha-phenylglycine precursor. Terminally protected homodi-, homotri-, and homotetrapeptides from Calpha-methyl, Calpha-cyclohexylglycine and co-oligopeptides to the pentamer level in combination with Gly or alpha-aminoisobutyric acid residues were prepared by solution methods and fully characterized. The results of a conformational analysis, performed by use of Fourier transform infrared (FT-IR) spectrophotometer absorption, 1H NMR, and X-ray diffraction techniques, support the contention that this Calpha-methylated, Cbeta-trisubstituted aliphatic alpha-amino acid is an effective beta-turn and 3(10)-helix inducer in tri- and longer peptides as its Calpha-methyl valine parent compound, but partially divergent from the corresponding aromatic Calpha-methyl, Calpha-diphenylmethylglycine residue, known to promote folded and fully extended structures to a significant extent in these oligomers.

MeSH terms

  • Alanine / analogs & derivatives
  • Alanine / chemistry*
  • Amino Acids / chemical synthesis
  • Amino Acids / chemistry
  • Crystallography, X-Ray
  • Glycine / analogs & derivatives
  • Glycine / chemistry
  • Magnetic Resonance Spectroscopy
  • Oligopeptides / chemical synthesis
  • Oligopeptides / chemistry*
  • Protein Conformation

Substances

  • Amino Acids
  • C(alpha)-methyl-C(alpha)-cyclohexylglycine
  • Oligopeptides
  • Alanine
  • Glycine