scholarly journals Protonation state of the Cu4S2CuZsite in nitrous oxide reductase: redox dependence and insight into reactivity

2015 ◽  
Vol 6 (10) ◽  
pp. 5670-5679 ◽  
Author(s):  
Esther M. Johnston ◽  
Simone Dell'Acqua ◽  
Sofia R. Pauleta ◽  
Isabel Moura ◽  
Edward I. Solomon
Keyword(s):  
Electron Transfer ◽  
Nitrous Oxide ◽  
Redox State ◽  
Nitrous Oxide Reductase ◽  
Protonation State ◽  
Proton Coupled Electron Transfer ◽  
Insight Into

The edge ligand in the Cu4S2CuZform of nitrous oxide reductase is a μ2-thiolate in the 1-hole and a μ2-sulfide in the 2-hole redox state, leading to proton-coupled electron transfer reactivity.

scholarly journals Biochemical characterization of the purple form of Marinobacter hydrocarbonoclasticus nitrous oxide reductase

2012 ◽  
Vol 367 (1593) ◽  
pp. 1204-1212 ◽  
Author(s):  
Simone Dell'Acqua ◽  
Sofia R. Pauleta ◽  
José J. G. Moura ◽  
Isabel Moura
Keyword(s):  
Nitrous Oxide ◽  
Redox State ◽  
Biochemical Characterization ◽  
Specific Activity ◽  
Active Species ◽  
Nitrous Oxide Reductase ◽  
Strictly Anaerobic ◽  
Prolonged Incubation ◽  
Redox Active ◽  
Marinobacter Hydrocarbonoclasticus

Nitrous oxide reductase (N 2 OR) catalyses the final step of the denitrification pathway—the reduction of nitrous oxide to nitrogen. The catalytic centre (CuZ) is a unique tetranuclear copper centre bridged by inorganic sulphur in a tetrahedron arrangement that can have different oxidation states. Previously, Marinobacter hydrocarbonoclasticus N 2 OR was isolated with the CuZ centre as CuZ*, in the [1Cu 2+ : 3Cu + ] redox state, which is redox inert and requires prolonged incubation under reductive conditions to be activated. In this work, we report, for the first time, the isolation of N 2 OR from M. hydrocarbonoclasticus in the ‘purple’ form, in which the CuZ centre is in the oxidized [2Cu 2+ : 2Cu + ] redox state and is redox active. This form of the enzyme was isolated in the presence of oxygen from a microaerobic culture in the presence of nitrate and also from a strictly anaerobic culture. The purple form of the enzyme was biochemically characterized and was shown to be a redox active species, although it is still catalytically non-competent, as its specific activity is lower than that of the activated fully reduced enzyme and comparable with that of the enzyme with the CuZ centre in either the [1Cu 2+ : 3Cu + ] redox state or in the redox inactive CuZ* state.

scholarly journals Anomalous chemically induced electron spin polarization in proton-coupled electron transfer reactions: insight into radical pair dynamics

2020 ◽  
Vol 11 (24) ◽  
pp. 6268-6274
Author(s):  
Alexander M. Brugh ◽  
Malcolm D. E. Forbes
Keyword(s):  
Electron Transfer ◽  
Ruthenium Complex ◽  
Transfer Reactions ◽  
Electron Spin Polarization ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
Proton Coupled Electron Transfer ◽  
Chemically Induced ◽  
Electron Paramagnetic ◽  
Insight Into

Time-resolved electron paramagnetic resonance (TREPR) spectroscopy has been used to study the proton coupled electron transfer (PCET) reaction between a Ruthenium complex (Ru(bpz)(bpy)2) and several substituted hydroquinones (HQ).

Insight into Catalysis of Nitrous Oxide Reductase from High-resolution Structures of Resting and Inhibitor-bound Enzyme from Achromobacter cycloclastes

2006 ◽  
Vol 362 (1) ◽  
pp. 55-65 ◽  
Author(s):  
Konstantinos Paraskevopoulos ◽  
Svetlana V. Antonyuk ◽  
R. Gary Sawers ◽  
Robert R. Eady ◽  
S. Samar Hasnain
Keyword(s):  
Nitrous Oxide ◽  
High Resolution ◽  
Nitrous Oxide Reductase ◽  
Achromobacter Cycloclastes ◽  
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