Chain-length-dependent helical motifs and self-association of beta-peptides with constrained side chains

J Am Chem Soc. 2005 Jan 19;127(2):547-53. doi: 10.1021/ja0475095.

Abstract

Homo-oligomers constructed by using trans-2-aminocyclohexanecarboxylic acid monomers without protecting groups were studied. Both ab initio theory and NMR measurements showed that the tetramer tends to adopt a 10-helix motif, while the pentamer and hexamer form the known 14-helix. It was concluded that the conformationally constrained backbone is flexible enough to afford both 10-helical and 14-helical motifs, this observation in turn providing evidence of the true folding process. Self-association of the helical units was also detected, and the results of variable-temperature diffusion NMR measurements strongly suggested the presence of helical bundles in methanol solution.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • Cyclohexanecarboxylic Acids / chemistry*
  • Cyclohexylamines / chemistry*
  • Deuterium
  • Models, Molecular
  • Nuclear Magnetic Resonance, Biomolecular / methods
  • Oligopeptides / chemistry*
  • Protein Structure, Secondary
  • Thermodynamics

Substances

  • Cyclohexanecarboxylic Acids
  • Cyclohexylamines
  • Oligopeptides
  • 2-aminocyclohexanecarboxylic acid
  • Deuterium