Interplay between Substrate and Proton Donor Coordination in Reductions of Carbonyls by SmI2–Water Through Proton-Coupled Electron-Transfer

2018 ◽  
Vol 140 (45) ◽  
pp. 15342-15352 ◽  
Author(s):  
Tesia V. Chciuk ◽  
William R. Anderson ◽  
Robert A. Flowers
Keyword(s):  
Electron Transfer ◽  
Proton Donor ◽  
Proton Coupled Electron Transfer ◽  
Donor Coordination

scholarly journals Visualizing the protons in a metalloenzyme electron proton transfer pathway

2020 ◽  
Vol 117 (12) ◽  
pp. 6484-6490 ◽  
Author(s):  
Hanna Kwon ◽  
Jaswir Basran ◽  
Juliette M. Devos ◽  
Reynier Suardíaz ◽  
Marc W. van der Kamp ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Transfer ◽  
Hydrogen Bonding ◽  
Proton Transfer ◽  
Proton Donor ◽  
Biological Processes ◽  
Proton Coupled Electron Transfer ◽  
Neutron Structure ◽  
Bona Fide ◽  
Electron Proton Transfer

In redox metalloenzymes, the process of electron transfer often involves the concerted movement of a proton. These processes are referred to as proton-coupled electron transfer, and they underpin a wide variety of biological processes, including respiration, energy conversion, photosynthesis, and metalloenzyme catalysis. The mechanisms of proton delivery are incompletely understood, in part due to an absence of information on exact proton locations and hydrogen bonding structures in a bona fide metalloenzyme proton pathway. Here, we present a 2.1-Å neutron crystal structure of the complex formed between a redox metalloenzyme (ascorbate peroxidase) and its reducing substrate (ascorbate). In the neutron structure of the complex, the protonation states of the electron/proton donor (ascorbate) and all of the residues involved in the electron/proton transfer pathway are directly observed. This information sheds light on possible proton movements during heme-catalyzed oxygen activation, as well as on ascorbate oxidation.

scholarly journals Proton-coupled electron transfer reactions: analytical rate constants and case study of kinetic isotope effects in lipoxygenase

2016 ◽  
Vol 195 ◽  
pp. 171-189 ◽  
Author(s):  
Alexander V. Soudackov ◽  
Sharon Hammes-Schiffer
Keyword(s):  
Electron Transfer ◽  
Rate Constant ◽  
Isotope Effects ◽  
Thermal Fluctuations ◽  
Proton Donor ◽  
Nonadiabatic Transitions ◽  
Proton Coupled Electron Transfer ◽  
Wide Range ◽  
Donor Acceptor ◽  
Vibronic States

A general theory has been developed for proton-coupled electron transfer (PCET), which is vital to a wide range of chemical and biological processes. This theory describes PCET reactions in terms of nonadiabatic transitions between reactant and product electron–proton vibronic states and includes the effects of thermal fluctuations of the solvent or protein environment, as well as the proton donor–acceptor motion. Within the framework of this general PCET theory, a series of analytical rate constant expressions has been derived for PCET reactions in well-defined regimes. Herein, the application of this theory to PCET in the enzyme soybean lipoxygenase illustrates the regimes of validity for the various rate constant expressions and elucidates the fundamental physical principles dictating PCET reactions. Such theoretical studies provide significant physical insights that guide the interpretation of experimental data and lead to experimentally testable predictions. A combination of theoretical treatments with atomic-level simulations is essential to understanding PCET.

scholarly journals Electron–Nuclear Dynamics Accompanying Proton-Coupled Electron Transfer

2021 ◽  
Vol 143 (8) ◽  
pp. 3104-3112
Author(s):  
Yusuke Yoneda ◽  
S. Jimena Mora ◽  
James Shee ◽  
Brian L. Wadsworth ◽  
Eric A. Arsenault ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Nuclear Dynamics ◽  
Proton Coupled Electron Transfer

Facile proton-coupled electron transfer enabled by coordination-induced E–H bond weakening to boron

2021 ◽  
Author(s):  
Anthony Wong ◽  
Arunavo Chakraborty ◽  
Deependra Bawari ◽  
Guang Wu ◽  
Roman Dobrovetsky ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Proton Coupled Electron Transfer

Coordination induced bond weakening (CIBW) leads to facile PCET at various E–H bonds.

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