Electron transfer and coupled processes in protein film voltammetry

1999 ◽  
Vol 27 (2) ◽  
pp. 206-210 ◽  
Author(s):  
F. A. Armstrong
Keyword(s):  
Electron Transfer ◽  
Coupled Processes ◽  
Protein Film ◽  
Protein Film Voltammetry

scholarly journals Mind the gap: diversity and reactivity relationships among multihaem cytochromes of the MtrA/DmsE family

2012 ◽  
Vol 40 (6) ◽  
pp. 1268-1273 ◽  
Author(s):  
Kathryn D. Bewley ◽  
Mackenzie A. Firer-Sherwood ◽  
Jee-Young Mock ◽  
Nozomi Ando ◽  
Catherine L. Drennan ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Membrane Proteins ◽  
Outer Membrane ◽  
Outer Membrane Proteins ◽  
Evolutionary Relationship ◽  
Shewanella Oneidensis ◽  
Anaerobic Respiration ◽  
Electron Acceptors ◽  
Protein Film ◽  
Protein Film Voltammetry

Shewanella oneidensis MR-1 has the ability to use many external terminal electron acceptors during anaerobic respiration, such as DMSO. The pathway that facilitates this electron transfer includes the decahaem cytochrome DmsE, a paralogue of the MtrA family of decahaem cytochromes. Although both DmsE and MtrA are decahaem cytochromes implicated in the long-range electron transfer across a ~300 Å (1 Å=0.1 nm) wide periplasmic ‘gap’, MtrA has been shown to be only 105 Å in maximal length. In the present paper, DmsE is further characterized via protein film voltammetry, revealing that the electrochemistry of the DmsE haem cofactors display macroscopic potentials lower than those of MtrA by 100 mV. It is possible this tuning of the redox potential of DmsE is required to shuttle electrons to the outer-membrane proteins specific to DMSO reduction. Other decahaem cytochromes found in S. oneidensis, such as the outer-membrane proteins MtrC, MtrF and OmcA, have been shown to have electrochemical properties similar to those of MtrA, yet possess a different evolutionary relationship.

Protein film voltammetry and co-factor electron transfer dynamics in spinach photosystem II core complex

2013 ◽  
Vol 120 (1-2) ◽  
pp. 153-167 ◽  
Author(s):  
Yun Zhang ◽  
Nikki Magdaong ◽  
Harry A. Frank ◽  
James F. Rusling
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Core Complex ◽  
Protein Film ◽  
Protein Film Voltammetry

scholarly journals Evidence for Distinct Electron Transfer Processes in Terminal Oxidases from Different Origin by Means of Protein Film Voltammetry

2014 ◽  
Vol 136 (31) ◽  
pp. 10854-10857 ◽  
Author(s):  
Thomas Meyer ◽  
Frédéric Melin ◽  
Hao Xie ◽  
Iris von der Hocht ◽  
Sylvia K. Choi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Protein Film ◽  
Protein Film Voltammetry ◽  
Terminal Oxidases ◽  
Transfer Processes ◽  
Electron Transfer Processes ◽  
Different Origin

Protein Film Voltammetry ofRhodobacterCapsulatusXanthine Dehydrogenase

2003 ◽  
Vol 125 (50) ◽  
pp. 15352-15358 ◽  
Author(s):  
Kondo François Aguey-Zinsou ◽  
Paul V. Bernhardt ◽  
Silke Leimkühler
Keyword(s):  
Protein Film ◽  
Protein Film Voltammetry

Voltammetric characterization of the aerobic energy-dissipating nitrate reductase of Paracoccus pantotrophus: exploring the activity of a redox-balancing enzyme as a function of electrochemical potential

2007 ◽  
Vol 409 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Andrew J. Gates ◽  
David J. Richardson ◽  
Julea N. Butt
Keyword(s):  
Nitrate Reductase ◽  
Nitrate Reduction ◽  
Reductase Activity ◽  
Electrochemical Potential ◽  
Intact Cells ◽  
Protein Film ◽  
Protein Film Voltammetry ◽  
Voltammetric Studies ◽  
Paracoccus Pantotrophus

Paracoccus pantotrophus expresses two nitrate reductases associated with respiratory electron transport, termed NapABC and NarGHI. Both enzymes derive electrons from ubiquinol to reduce nitrate to nitrite. However, while NarGHI harnesses the energy of the quinol/nitrate couple to generate a transmembrane proton gradient, NapABC dissipates the energy associated with these reducing equivalents. In the present paper we explore the nitrate reductase activity of purified NapAB as a function of electrochemical potential, substrate concentration and pH using protein film voltammetry. Nitrate reduction by NapAB is shown to occur at potentials below approx. 0.1 V at pH 7. These are lower potentials than required for NarGH nitrate reduction. The potentials required for Nap nitrate reduction are also likely to require ubiquinol/ubiquinone ratios higher than are needed to activate the H+-pumping oxidases expressed during aerobic growth where Nap levels are maximal. Thus the operational potentials of P. pantotrophus NapAB are consistent with a productive role in redox balancing. A Michaelis constant (KM) of approx. 45 μM was determined for NapAB nitrate reduction at pH 7. This is in line with studies on intact cells where nitrate reduction by Nap was described by a Monod constant (KS) of less than 15 μM. The voltammetric studies also disclosed maximal NapAB activity in a narrow window of potential. This behaviour is resistant to change of pH, nitrate concentration and inhibitor concentration and its possible mechanistic origins are discussed.

Very Rapid, Cooperative Two-Electron/Two-Proton Redox Reactions of [3Fe−4S] Clusters:  Detection and Analysis by Protein-Film Voltammetry

1998 ◽  
Vol 120 (46) ◽  
pp. 11994-11999 ◽  
Author(s):  
Judy Hirst ◽  
Guy N. L. Jameson ◽  
James W. A. Allen ◽  
Fraser A. Armstrong
Keyword(s):  
Redox Reactions ◽  
Protein Film ◽  
Protein Film Voltammetry
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