Ultrafast Chemical Exchange Dynamics of Hydrogen Bonds Observed via Isonitrile Infrared Sensors: Implications for Biomolecular Studies

Joachim Kübel, Giseong Lee, Saik Ann Ooi, Sebastian Westenhoff, Hogyu Han, Minhaeng Cho, Michał Maj

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Local probes are indispensable to study protein structure and dynamics with site-specificity. The isonitrile functional group is a highly sensitive and H-bonding interaction-specific probe. Isonitriles exhibit large spectral shifts and transition dipole moment changes upon H-bonding while being weakly affected by solvent polarity. These unique properties allow a clear separation of distinct subpopulations of interacting species and an elucidation of their ultrafast dynamics with two-dimensional infrared (2D-IR) spectroscopy. Here, we apply 2D-IR to quantify the picosecond chemical exchange dynamics of solute-solvent complexes forming between isonitrile-derivatized alanine and fluorinated ethanol, where the degree of fluorination controls their H-bond-donating ability. We show that the molecules undergo faster exchange in the presence of more acidic H-bond donors, indicating that the exchange process is primarily dependent on the nature of solvent-solvent interactions. We foresee isonitrile as a highly promising probe for studying of H-bonds dynamics in the active site of enzymes.

Original languageEnglish
Pages (from-to)7878-7883
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume10
Issue number24
DOIs
Publication statusPublished - 2019 Dec 19

Bibliographical note

Funding Information:
This work was supported by IBS-R023-D1 (MC). S.W. thanks the Knut and Alice Wallenberg Foundation for an Academy Fellowship. H.H. is grateful for the financial support from the National Research Foundation (NRF) of Korea funded by Ministry of Science and ICT (NRF2019R1H1A2079948).

Publisher Copyright:
© 2019 American Chemical Society.

ASJC Scopus subject areas

  • General Materials Science
  • Physical and Theoretical Chemistry

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