Abstract
Proton-coupled electron transfer (PCET) plays a vital role in many biological and chemical processes. PCET rate constant expressions are available for various well-defined regimes, and determining which expression is appropriate for a given system is essential for reliable modeling. Quantitative diagnostics have been devised to characterize the vibronic nonadiabaticity between the electron-proton quantum subsystem and the classical nuclei, as well as the electron-proton nonadiabaticity between the electrons and proton(s) within the quantum subsystem. Herein these diagnostics are applied to a model of the active site of the enzyme soybean lipoxygenase, which catalyzes a PCET reaction that exhibits unusually high deuterium kinetic isotope effects at room temperature. Both semiclassical and electronic charge density diagnostics illustrate vibronic and electron-proton nonadiabaticity for this PCET reaction, supporting the use of the Golden rule nonadiabatic rate constant expression with a specific form of the vibronic coupling. This type of characterization will be useful for theoretical modeling of a broad range of PCET processes.
Original language | English (US) |
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Pages (from-to) | 3274-3278 |
Number of pages | 5 |
Journal | Journal of Physical Chemistry Letters |
Volume | 5 |
Issue number | 18 |
DOIs | |
State | Published - Sep 18 2014 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- General Materials Science
- Physical and Theoretical Chemistry
Keywords
- Biophysical chemistry and biomolecules