Quantifying the intrinsic effects of two point mutation models of Pro-Pro-Pro triamino acid diamide. A first-principle computational study

Michelle A. Sahai, Bela Viskolcz, Emil F. Pai, Imre G. Csizmadia

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Stabilities and conformational properties of two Pro → Thr point mutation models were computed at the B3LYP/6-31G(d) level of theory for the parent triamino acid diamide Pro-Pro-Pro (HCO-Pro-Pro-Pro-NH2). Geometrical parameters for the amino acid sequences, used in the molecular orbital computations for Pro-Pro-Thr and Pro-Thr-Pro, were retrieved from the Protein Data Bank. Thermodynamic functions (S, H, G) were computed for the fully optimized geometries. To assess the stabilization energetics of these mutant models, relative to the parent Pro-Pro-Pro reference conformer εLεLγL, isodesmic reactions were constructed to calculate ΔS, ΔH, and ΔG. The importance of intramolecular hydrogen bonds involving the -OH group of the Thr side chain, which emerged after the point mutations, was also examined to determine the internal stabilization of these peptide models. This study describes an approach to analyzing a point mutation at the center of a peptide chain and compares its stability to that of a point mutation at a terminal end in a small peptide model.

Original languageEnglish
Pages (from-to)13135-13142
Number of pages8
JournalJournal of Physical Chemistry B
Volume111
Issue number45
DOIs
Publication statusPublished - Nov 15 2007

ASJC Scopus subject areas

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

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