The folded, partially folded, misfolded, and unfolded conformations of cytochrome c probed by optical spectroscopy

2021 ◽  
Author(s):  
Jonathan Barrot Soffer
Keyword(s):  
Cytochrome C ◽  
Optical Spectroscopy

scholarly journals An investigation by e.p.r. and optical spectroscopy of cytochrome oxidase during turnover

1982 ◽  
Vol 203 (2) ◽  
pp. 483-492 ◽  
Author(s):  
M T Wilson ◽  
P Jensen ◽  
R Aasa ◽  
B G Malmström ◽  
T Vänngård
Keyword(s):  
Steady State ◽  
Cytochrome C ◽  
Cytochrome Oxidase ◽  
Optical Spectroscopy ◽  
High Spin ◽  
Electron Flux ◽  
Turnover Rates ◽  
G 12 ◽  
Radical Signal ◽  
O2 Binding

Cytochrome oxidase (EC 1.9.3.1; ferrocytochrome c:oxygen oxidoreductase) was studied during steady-state by optical and e.p.r. methods. Starting with either the ‘resting’ or the ‘pulsed’ enzyme, oxidase, cytochrome c, ascorbate and O2 were mixed and the reaction monitored optically. Tetramethylphenylenediamine was used as mediator to poise the steady-state to the desired reduction level. After mixing, the reaction was quenched by the used of rapid-freeze techniques. The e.p.r. spectra of samples captured at increasing tetramethylphenylenediamine concentrations (i.e. higher electron flux) show decreasing g = 2 (Cu A) and g = 3 (cytochrome a) signals. No Cu B or g = 6 signals (high-spin cytochrome a3) could be found during the reaction. Also, the signal with peaks at g = 1.69, 1.78 and 5 as well as the g = 12 signal was hardly detectable at higher turnover rates. The only new signal appearing during turnover is a radical signal, which is discussed in terms of a protein radical. Finally, a scheme is presented, proposing a catalytic cycle for cytochrome oxidase with respect to the O2 binding Cu B-cytochrome a3 unit.

Conformational Stability of Cytochrome c Probed by Optical Spectroscopy

2009 ◽  
pp. 109-153 ◽  
Author(s):  
Reinhard Schweitzer-Stenner ◽  
Andrew Hagarman ◽  
Daniel Verbaro ◽  
Jonathan B. Soffer
Keyword(s):  
Cytochrome C ◽  
Optical Spectroscopy ◽  
Conformational Stability

scholarly journals Noninvasive optical cytochrome c oxidase redox state measurements using diffuse optical spectroscopy

2014 ◽  
Vol 19 (5) ◽  
pp. 055001 ◽  
Author(s):  
Jangwoen Lee ◽  
Jae G. Kim ◽  
Sari B. Mahon ◽  
David Mukai ◽  
David Yoon ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Optical Spectroscopy ◽  
Redox State ◽  
Diffuse Optical Spectroscopy

Nucleic Acid Molecules Prepared by Monolayer Techniques

1972 ◽  
Vol 30 ◽  
pp. 178-179
Author(s):  
Dimitrij Lang
Keyword(s):  
Electron Microscopy ◽  
Standard Deviation ◽  
Nucleic Acid ◽  
Cytochrome C ◽  
Nucleic Acids ◽  
Contour Length ◽  
Sample Standard Deviation ◽  
Molecular Weights ◽  
Length Measurements ◽  
Protein Monolayer

The success of the protein monolayer technique for electron microscopy of individual DNA molecules is based on the prevention of aggregation and orientation of the molecules during drying on specimen grids. DNA adsorbs first to a surface-denatured, insoluble cytochrome c monolayer which is then transferred to grids, without major distortion, by touching. Fig. 1 shows three basic procedures which, modified or not, permit the study of various important properties of nucleic acids, either in concert with other methods or exclusively:1) Molecular weights relative to DNA standards as well as number distributions of molecular weights can be obtained from contour length measurements with a sample standard deviation between 1 and 4%.

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

Solution structure of cytochrome b5 mutant (E44/48/56A/D60A) and its interaction with cytochrome c

2001 ◽  
Vol 268 (6) ◽  
pp. 1620-1630
Author(s):  
Yibing Wu ◽  
Yunhua Wang ◽  
Chengmin Qian ◽  
Jun Lu ◽  
Ercheng Li ◽  
...  
Keyword(s):  
Cytochrome C ◽  
Solution Structure ◽  
Cytochrome B5

Expression of sunflower cytochrome c mRNA is tissue-specific and controlled by nitrate and light

1997 ◽  
Vol 99 (2) ◽  
pp. 342-347 ◽  
Author(s):  
Silvina A. Felitti ◽  
Raquel L. Chan ◽  
Gabriela Gago ◽  
Estela M. Valle ◽  
Daniel H. Gonzalez
Keyword(s):  
Cytochrome C ◽  
Tissue Specific
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