Computational Investigation of the Effect of Backbone Chiral Inversions on Polypeptide Structure

Gül H. Zerze, Mohammad Navaid Khan, Frank H. Stillinger, Pablo G. Debenedetti

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

Studying a set of helix-folding polyalanine peptides with systematically inserted chiral inversions in explicit water, we investigate quantitatively the effect of chiral perturbations on the structural ensembles of the peptides, thereby assessing the extent to which the backbone structure is able to fold in the presence of systematic heterochiral perturbations. Starting from the homochiral l-Ala20 peptide, we invert the backbone chiralities of Ala residues one by one along a specific perturbation pathway, until reaching the homochiral d-Ala20 peptide. Analysis of the helical contents of the simulated structural ensembles of the peptides shows that even a single inversion in the middle of the peptide completely breaks the helical structure in its vicinity and drastically reduces the helical content of the peptide. Further inversions in the middle of the peptide monotonically decrease the original helical content, that is, the right-handed helical content for l-Ala, and increase the helical content of the opposite chirality. Further analysis of the peptide ensembles using several size- and shape-related order parameters also indicate the drastic global changes in the peptide structure due to the local effects caused by the chiral inversions, such as formation of a reverse turn. However, the degree of the structural changes introduced by opposite chirality substitutions depends on the position of the inversion.

Original languageEnglish (US)
Pages (from-to)6357-6363
Number of pages7
JournalJournal of Physical Chemistry B
Volume122
Issue number24
DOIs
StatePublished - Jun 21 2018

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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