Interaction Enthalpy of Side Chain and Backbone Amides in Polyglutamine Solution Monomers and Fibrils

David Punihaole, Ryan S. Jakubek, Riley Workman, Sanford A. Asher

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

We determined an empirical correlation that relates the amide I vibrational band frequencies of the glutamine (Q) side chain to the strength of hydrogen bonding, van der Waals, and Lewis acid-base interactions of its primary amide carbonyl. We used this correlation to determine the Q side chain carbonyl interaction enthalpy (ΔHint) in monomeric and amyloid-like fibril conformations of D2Q10K2 (Q10). We independently verified these ΔHint values through molecular dynamics simulations that showed excellent agreement with experiments. We found that side chain-side chain and side chain-peptide backbone interactions in fibrils and monomers are more enthalpically favorable than are Q side chain-water interactions. Q10 fibrils also showed a more favorable ΔHint for side chain-side chain interactions compared to backbone-backbone interactions. This work experimentally demonstrates that interamide side chain interactions are important in the formation and stabilization of polyQ fibrils.

Original languageEnglish (US)
Pages (from-to)1944-1950
Number of pages7
JournalJournal of Physical Chemistry Letters
Volume9
Issue number8
DOIs
StatePublished - Apr 19 2018
Externally publishedYes

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Amides
amides
Enthalpy
monomers
Monomers
enthalpy
Lewis Acids
Glutamine
Amyloid
Peptides
Frequency bands
Conformations
Molecular dynamics
Hydrogen bonds
Stabilization
interactions
Acids
Water
Computer simulation
Experiments

ASJC Scopus subject areas

  • Materials Science(all)

Cite this

Interaction Enthalpy of Side Chain and Backbone Amides in Polyglutamine Solution Monomers and Fibrils. / Punihaole, David; Jakubek, Ryan S.; Workman, Riley; Asher, Sanford A.

In: Journal of Physical Chemistry Letters, Vol. 9, No. 8, 19.04.2018, p. 1944-1950.

Research output: Contribution to journalArticle

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