Probing nonadiabaticity in the proton-coupled electron transfer reaction catalyzed by Soybean Lipoxygenase

Alexander V. Soudackov, Sharon Hammes-Schiffer

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

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 languageEnglish (US)
Pages (from-to)3274-3278
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume5
Issue number18
DOIs
StatePublished - Sep 18 2014
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physical and Theoretical Chemistry

Keywords

  • Biophysical chemistry and biomolecules

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