Aromatic-backbone interactions in model α-helical peptides

Nicholas Y. Palermo, József Csontos, Michael C. Owen, Richard F. Murphy, Sándor Lovas

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


The effects on helical stability of weak polar interactions between aromatic side-chains and the peptide backbone were examined. α-Helical model peptides, hexa-Ala, with sequential Tyr replacement, were investigated computationally to obtain the geometries and energetics of the interactions. Geometries were obtained with the B3LYP/6-31G* level of theory. Interaction energies were calculated using BHandHLYP/cc-pVTZ and an improved method to correct for basis set superposition error when fragmentation caused steric clashes. Both i, i + 1 and i, i - 4 interactions were observed when Tyr was in position i = 5. The position of the aromatic residue in the amino acid sequence was crucial in facilitating aromatic-backbone interactions. The distance between the center of the aromatic ring of Tyr and the individual interacting backbone atoms ranged from 3.65 to 5.50 A. The interactions have energies of the same order as hydrogen bonds and, thus, could have a significant impact on the stability of the helix.

Original languageEnglish (US)
Pages (from-to)1208-1214
Number of pages7
JournalJournal of Computational Chemistry
Issue number7
StatePublished - May 2007
Externally publishedYes


  • Aromatic-backbone interactions
  • BSSE corrected interaction energies
  • Density functional theory
  • Helices
  • Weakly polar interactions

ASJC Scopus subject areas

  • General Chemistry
  • Computational Mathematics


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