Coordination dynamics of heme-copper oxidases. The ligand shuttle and the control and coupling of electron transfer and proton translocation

1993 ◽  
Vol 25 (2) ◽  
pp. 177-188 ◽  
Author(s):  
William H. Woodruff
Keyword(s):  
Electron Transfer ◽  
Proton Translocation ◽  
Coordination Dynamics ◽  
Heme Copper Oxidases

scholarly journals Mutation of a single residue in the ba3 oxidase specifically impairs protonation of the pump site

2015 ◽  
Vol 112 (11) ◽  
pp. 3397-3402 ◽  
Author(s):  
Christoph von Ballmoos ◽  
Nathalie Gonska ◽  
Peter Lachmann ◽  
Robert B. Gennis ◽  
Pia Ädelroth ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Time Constant ◽  
Thermus Thermophilus ◽  
Proton Translocation ◽  
Proton Pumping ◽  
Wild Type ◽  
Structural Variant ◽  
In The Wild ◽  
Membrane Bound ◽  
Proton Uptake

The ba3-type cytochrome c oxidase from Thermus thermophilus is a membrane-bound protein complex that couples electron transfer to O2 to proton translocation across the membrane. To elucidate the mechanism of the redox-driven proton pumping, we investigated the kinetics of electron and proton transfer in a structural variant of the ba3 oxidase where a putative “pump site” was modified by replacement of Asp372 by Ile. In this structural variant, proton pumping was uncoupled from internal electron transfer and O2 reduction. The results from our studies show that proton uptake to the pump site (time constant ∼65 μs in the wild-type cytochrome c oxidase) was impaired in the Asp372Ile variant. Furthermore, a reaction step that in the wild-type cytochrome c oxidase is linked to simultaneous proton uptake and release with a time constant of ∼1.2 ms was slowed to ∼8.4 ms, and in Asp372Ile was only associated with proton uptake to the catalytic site. These data identify reaction steps that are associated with protonation and deprotonation of the pump site, and point to the area around Asp372 as the location of this site in the ba3 cytochrome c oxidase.

Oxygen Reduction and Proton Translocation by the Heme-Copper Oxidases

1999 ◽  
pp. 193-217 ◽  
Author(s):  
Mårten Wikström ◽  
Joel E. Morgan ◽  
Gerhard Hummer ◽  
William H. Woodruff ◽  
Michael I. Verkhovsky
Keyword(s):  
Oxygen Reduction ◽  
Proton Translocation ◽  
Heme Copper Oxidases

scholarly journals Structure and mechanism of the Mrp complex, an ancient cation/proton antiporter

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Julia Steiner ◽  
Leonid Sazanov
Keyword(s):  
Electron Transfer ◽  
Electrostatic Interactions ◽  
Proton Translocation ◽  
Proton Pumps ◽  
Entire Family ◽  
Surface Charge Distribution ◽  
Large Protein Family ◽  
Anoxybacillus Flavithermus ◽  
Respiratory Complex I ◽  
Ph Adaptation

Multiple resistance and pH adaptation (Mrp) antiporters are multi-subunit Na+ (or K+)/H+ exchangers representing an ancestor of many essential redox-driven proton pumps, such as respiratory complex I. The mechanism of coupling between ion or electron transfer and proton translocation in this large protein family is unknown. Here, we present the structure of the Mrp complex from Anoxybacillus flavithermus solved by cryo-EM at 3.0 Å resolution. It is a dimer of seven-subunit protomers with 50 trans-membrane helices each. Surface charge distribution within each monomer is remarkably asymmetric, revealing probable proton and sodium translocation pathways. On the basis of the structure we propose a mechanism where the coupling between sodium and proton translocation is facilitated by a series of electrostatic interactions between a cation and key charged residues. This mechanism is likely to be applicable to the entire family of redox proton pumps, where electron transfer to substrates replaces cation movements.

Proton-Coupled Electron Transfer Drives Long-Range Proton Translocation in Bioinspired Systems

2019 ◽  
Vol 141 (36) ◽  
pp. 14057-14061 ◽  
Author(s):  
Emmanuel Odella ◽  
Brian L. Wadsworth ◽  
S. Jimena Mora ◽  
Joshua J. Goings ◽  
Mioy T. Huynh ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Long Range ◽  
Proton Translocation ◽  
Proton Coupled Electron Transfer

scholarly journals Five decades of research on mitochondrial NADH-quinone oxidoreductase (complex I)

2018 ◽  
Vol 399 (11) ◽  
pp. 1249-1264 ◽  
Author(s):  
Tomoko Ohnishi ◽  
S. Tsuyoshi Ohnishi ◽  
John C. Salerno
Keyword(s):  
Electron Transfer ◽  
Respiratory Chain ◽  
Complex I ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Mitochondrial Respiratory Chain ◽  
Proton Pumping ◽  
Entry Site ◽  
Quinone Oxidoreductase ◽  
Terminal Electron Acceptor

AbstractNADH-quinone oxidoreductase (complex I) is the largest and most complicated enzyme complex of the mitochondrial respiratory chain. It is the entry site into the respiratory chain for most of the reducing equivalents generated during metabolism, coupling electron transfer from NADH to quinone to proton translocation, which in turn drives ATP synthesis. Dysfunction of complex I is associated with neurodegenerative diseases such as Parkinson’s and Alzheimer’s, and it is proposed to be involved in aging. Complex I has one non-covalently bound FMN, eight to 10 iron-sulfur clusters, and protein-associated quinone molecules as electron transport components. Electron paramagnetic resonance (EPR) has previously been the most informative technique, especially in membranein situanalysis. The structure of complex 1 has now been resolved from a number of species, but the mechanisms by which electron transfer is coupled to transmembrane proton pumping remains unresolved. Ubiquinone-10, the terminal electron acceptor of complex I, is detectable by EPR in its one electron reduced, semiquinone (SQ) state. In the aerobic steady state of respiration the semi-ubiquinone anion has been observed and studied in detail. Two distinct protein-associated fast and slow relaxing, SQ signals have been resolved which were designated SQNfand SQNs. This review covers a five decade personal journey through the field leading to a focus on the unresolved questions of the role of the SQ radicals and their possible part in proton pumping.

The histidine cycle: A new model for proton translocation in the respiratory heme-copper oxidases

1994 ◽  
Vol 26 (6) ◽  
pp. 599-608 ◽  
Author(s):  
Joel E. Morgan ◽  
Michael I. Verkhovsky ◽  
M�rten Wikstr�m
Keyword(s):  
Proton Translocation ◽  
New Model ◽  
Heme Copper Oxidases
Sign in / Sign up

Export Citation Format

Share Document