Electron-paramagnetic-resonance studies of structure and function of the two-haem enzymes Pseudomonas cytochrome c peroxidase and beef heart cytochrome c oxidase

1985 ◽  
Vol 13 (3) ◽  
pp. 619-622 ◽  
Author(s):  
TORE VÄNNGÅRD
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Cytochrome C Peroxidase ◽  
Structure And Function ◽  
Beef Heart ◽  
Paramagnetic Resonance ◽  
And Function ◽  
Electron Paramagnetic

scholarly journals Angular Dependences of Perpendicular and Parallel Mode Electron Paramagnetic Resonance of Oxidized Beef Heart Cytochrome c Oxidase

2000 ◽  
Vol 78 (1) ◽  
pp. 439-450 ◽  
Author(s):  
Dominic J.B. Hunter ◽  
Vasily S. Oganesyan ◽  
John C. Salerno ◽  
Clive S. Butler ◽  
W. John Ingledew ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Beef Heart ◽  
Paramagnetic Resonance ◽  
Parallel Mode ◽  
Electron Paramagnetic

Nanoscale lipid membrane mimetics in spin-labeling and electron paramagnetic resonance spectroscopy studies of protein structure and function

2017 ◽  
Vol 6 (1) ◽  
pp. 75-92 ◽  
Author(s):  
Elka R. Georgieva
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Protein Structure ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Spin Labeling ◽  
Structure And Function ◽  
Protein Structure And Function ◽  
Paramagnetic Resonance ◽  
And Function ◽  
Electron Paramagnetic

AbstractCellular membranes and associated proteins play critical physiological roles in organisms from all life kingdoms. In many cases, malfunction of biological membranes triggered by changes in the lipid bilayer properties or membrane protein functional abnormalities lead to severe diseases. To understand in detail the processes that govern the life of cells and to control diseases, one of the major tasks in biological sciences is to learn how the membrane proteins function. To do so, a variety of biochemical and biophysical approaches have been used in molecular studies of membrane protein structure and function on the nanoscale. This review focuses on electron paramagnetic resonance with site-directed nitroxide spin-labeling (SDSL EPR), which is a rapidly expanding and powerful technique reporting on the local protein/spin-label dynamics and on large functionally important structural rearrangements. On the other hand, adequate to nanoscale study membrane mimetics have been developed and used in conjunction with SDSL EPR. Primarily, these mimetics include various liposomes, bicelles, and nanodiscs. This review provides a basic description of the EPR methods, continuous-wave and pulse, applied to spin-labeled proteins, and highlights several representative applications of EPR to liposome-, bicelle-, or nanodisc-reconstituted membrane proteins.

scholarly journals Interactions of sulphide and other ligands with cytochrome c oxidase. An electron-paramagnetic-resonance study

1984 ◽  
Vol 224 (2) ◽  
pp. 591-600 ◽  
Author(s):  
B C Hill ◽  
T C Woon ◽  
P Nicholls ◽  
J Peterson ◽  
C Greenwood ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Electron Paramagnetic Resonance Study ◽  
Optical Absorption Spectroscopy ◽  
Reactivity Pattern ◽  
Paramagnetic Resonance ◽  
Point Potential ◽  
G 12 ◽  
Electron Paramagnetic

The effect of sulphide on resting oxidized cytochrome c oxidase was studied by both e.p.r. and optical-absorption spectroscopy. Excess sulphide causes some reduction of cytochrome a, CuA and CuB, and the formation of the cytochrome a3-SH complex after about 1 min. After several hours in the presence of excess sulphide only the e.p.r. signals due to low-spin ferricytochrome a3-SH persist, giving a partially reduced species. Re-oxidation of this partially reduced sulphide-bound enzyme by ferricyanide makes all of the metal centres except CuB detectable by e.p.r. We conclude that sulphide has reduced and binds to CuB as well as to ferricytochrome a3. Sulphide binding to cuprous CuB may raise its mid-point potential and make re-oxidation difficult. Addition of reductant (ascorbate + NNN'N'-tetramethyl-p-phenylenediamine) and sulphide together to the oxidized resting enzyme produces a species in which cytochrome a and CuA are nearly completely reduced and cytochrome a3 is e.p.r.-detectable as approx. 80% of one haem in the low-spin sulphide-bound complex. The g = 12 signal of this partially reduced derivative is almost unchanged in magnitude relative to that of the resting enzyme; this suggests that the g = 12 signal may arise from less than 20% of the enzyme and that it may be relatively unreactive to both ligation and reduction. Such a reactivity pattern of the g = 12 form of the oxidase is also demonstrated with the ligands F- and NO, which are thought to bind to cytochrome a3 and CuB respectively.

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