Substituent effects on long-range interactions in the β-sheet structure of oligopeptides

Viktória Horváth, Zoltán Varga, Attila Kovács

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Abstract

The energetic stabilization and geometrical parameters of the β-sheet structure of three oligopeptides L-Alan, selected conformers of L-Valn and L-Sern (n=2-10) have been investigated by DFT computations. The data reveal the important effect of long-range interactions operating through hydrogen bonding and dipole-dipole interactions. Compared with related data on Glyn oligopeptides determined in our previous study (V. Horváth, Z. Varga, A. Kovács, J. Phys. Chem. A, 2004, 108, 6869-6873), the methyl, i-propyl and hydroxymethyl substituents lead to a decrease of the long-range interactions. While the energy gain from these interactions of a Gly unit in Gly10 was 2.4 kJ/mol, the contribution decreased to 2.1, 1.8, and 0.4 kJ/mol in Ala10, Val10, and Ser10, respectively. Variations of the geometrical parameters (most important being the lengths of H⋯O hydrogen-bonds and the C-N bonds) are in agreement with the decrease of the stabilization energies. Another important effect of the substituents is that their steric interactions introduce irregularities in the build-up of energetic and geometric trends, in contrast to their monotonous build-up in Glyn.

Original languageEnglish
Pages (from-to)247-251
Number of pages5
JournalJournal of Molecular Structure: THEOCHEM
Volume755
Issue number1-3
DOIs
Publication statusPublished - Sep 15 2005

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Keywords

  • DFT
  • Geometry
  • Long-range interactions
  • Peptides

ASJC Scopus subject areas

  • Biochemistry
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

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