Synthesis and conformational analysis of (alpha Me)Leu/Aib model peptides

Pept Res. 1993 Jul-Aug;6(4):196-204.

Abstract

We have synthesized by solution methods and fully characterized a variety of (alpha Me)Leu/Aib model peptides to the octapeptide level. A solution conformational analysis was performed by using infrared absorption. 1H nuclear magnetic resonance, and circular dichroism. The crystal-state structures of Z-D-(alpha Me)Leu-(Aib)2-OtBu, pBrBz-(Aib)2-D-(alpha Me)Leu-(Aib)2-OtBu, and Ac-(Aib)2-D-(alpha Me)Leu-(Aib)2-OtBu monohydrate were solved by x-ray diffraction. The results indicate that the (alpha Me)Leu residue may be easily incorporated into beta-bends and 3(10)-helical structures, and suggest that this residue tends to induce a helix handedness opposite to that promoted by its unmethylated counterpart (Leu) of the same optical configuration.

MeSH terms

  • Aminoisobutyric Acids
  • Circular Dichroism
  • Crystallography, X-Ray
  • Leucine / chemistry*
  • Magnetic Resonance Spectroscopy
  • Peptides / chemical synthesis*
  • Protein Conformation*
  • Spectrophotometry, Infrared

Substances

  • Aminoisobutyric Acids
  • Peptides
  • 2-aminoisobutyric acid
  • Leucine