Pyrroloisoquinoline-based tetrapeptide analogues mimicking reverse-turn secondary structures

J Org Chem. 2007 Dec 7;72(25):9765-8. doi: 10.1021/jo701581j. Epub 2007 Nov 9.

Abstract

New pyrroloisoquinoline-based tetrapeptides were synthesized in enantiomerically pure form, and their conformational features were studied by NMR, IR, and molecular-modeling techniques. The presence of a reverse turn was observed in both structures, with the C1 stereochemistry playing a central role in determining stable conformations. In particular, all of the analyses led to the conclusion that a type II' beta-turn is mostly stabilized in tetrapeptide mimic 3a, while a typical inverse gamma-turn geometry is revealed for the diastereoisomer 3b.

MeSH terms

  • Isoquinolines / chemistry*
  • Magnetic Resonance Spectroscopy / methods
  • Models, Chemical
  • Models, Molecular
  • Molecular Conformation
  • Molecular Mimicry
  • Monte Carlo Method
  • Oligopeptides / chemical synthesis*
  • Oligopeptides / chemistry
  • Protein Structure, Secondary
  • Spectrophotometry, Infrared / methods
  • Stereoisomerism

Substances

  • Isoquinolines
  • Oligopeptides