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Oscillatory Enzyme Dynamics Revealed by Two-Dimensional Infrared Spectroscopy
Philip Pagano1, Qi Guo1, Amnon Kohen1
1Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
The Journal of Physical Chemistry Letters
|June 16, 2016
Summary
Fast enzyme motions were measured using 2D IR spectroscopy. Oscillations from the nicotinamide ring in formate dehydrogenase suggest insights into enzyme catalysis dynamics.
Area of Science:
- Biochemistry
- Chemical Physics
- Enzyme Dynamics
Background:
- Enzymes exhibit motions across various timescales, influencing substrate binding and product release.
- Faster enzymatic motions and their role in catalysis remain less understood.
- Investigating these dynamics offers insights into enzyme mechanisms.
Purpose of the Study:
- To investigate the influence of enzyme dynamics on catalytic reactions.
- To measure frequency fluctuations of an anion probe within an enzyme active site.
- To elucidate the role of cofactor interactions in enzyme motion.
Main Methods:
- Utilized 2D Infrared (2D IR) spectroscopy to probe frequency fluctuations.
- Employed azide anion as a vibrational probe within the formate dehydrogenase active site.
- Measured frequency-frequency correlation functions for the bound azide anion.
Main Results:
- Observed an underdamped oscillatory component in frequency fluctuations for azide bound to the NAD(+) ternary complex.
- This oscillation diminished upon addition of the reduced cofactor.
- Attributed the oscillatory motion to the charged nicotinamide ring of the cofactor.
Conclusions:
- Fast oscillatory motions originating from the nicotinamide ring are identified.
- These motions may play a role in sampling donor-acceptor distances for hydride transfer.
- Provides new insights into the dynamic behavior governing enzyme catalysis.
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