TY - JOUR
T1 - Ultrafast Chemical Exchange Dynamics of Hydrogen Bonds Observed via Isonitrile Infrared Sensors
T2 - Implications for Biomolecular Studies
AU - Kübel, Joachim
AU - Lee, Giseong
AU - Ooi, Saik Ann
AU - Westenhoff, Sebastian
AU - Han, Hogyu
AU - Cho, Minhaeng
AU - Maj, Michał
N1 - 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.
PY - 2019/12/19
Y1 - 2019/12/19
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85076560007&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.9b03144
DO - 10.1021/acs.jpclett.9b03144
M3 - Article
C2 - 31794222
AN - SCOPUS:85076560007
VL - 10
SP - 7878
EP - 7883
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 24
ER -