scholarly journals An antimycin A- and cyanide-resistant variant of Candida utilis arising during copper-limited growth

1973 ◽  
Vol 134 (4) ◽  
pp. 1051-1061 ◽  
Author(s):  
J. A. Downie ◽  
P. B. Garland
Keyword(s):  
Cytochrome Oxidase ◽  
Candida Utilis ◽  
Alternative Oxidase ◽  
Growth Parameters ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Limited Growth ◽  
Paramagnetic Resonance ◽  
Resistant Variant ◽  
Electron Paramagnetic

1. During copper-limited growth of Candida utilis in continuous culture on a non-fermentable carbon and energy source there is a selective pressure favouring the emergence of variants that are less dependent on copper. 2. We describe the properties of such a variant that by-passes cytochrome oxidase (EC 1.9.3.1) by utilizing an alternative oxidase communicating with the respiratory chain at about the level of cytochrome b. 3. Both direct studies of isolated mitochondria and calculations based on growth parameters showed that only one of the normal three phosphorylation sites was active. This site was localized between NADH and the cytochromes. 4. Growth of the variant with copper-supplemented media resulted in the return of cytochrome oxidase but not the loss of the alternative oxidase. 5. The alternative oxidase is inhibited by substituted benzhydroxamic acids. 6. Submitochondrial particles from the variant did not exhibit any novel electron-paramagnetic-resonance-spectroscopy features at about g=2.0 either at 80°K or 12°K.

scholarly journals Electron-paramagnetic-resonance spectroscopy studies of iron-sulphur centres of submitochondrial particles from iron- and sulphur-deficient. Candida utilis

1975 ◽  
Vol 146 (1) ◽  
pp. 239-246 ◽  
Author(s):  
T A Gray ◽  
P B Garland ◽  
D J Lowe ◽  
R C Bray
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Nadh Dehydrogenase ◽  
Candida Utilis ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Submitochondrial Particles ◽  
Limited Growth ◽  
Paramagnetic Resonance ◽  
Dehydrogenase Reaction ◽  
Electron Paramagnetic

1. Measurements were made at 12 degrees K of the electron-paramagnetic-resonance (e.p.r.) spectra of submitochondrial particles from Candida utilis cells grown under conditions that alter the amount of the mitochondrial NADH dehydrogenase (EC 1.6.99.3). 2. Iron-limited growth decreases the extent of iron-sulphur e.p.r. signals to undetectable values that are less than 1 percent of those normally found with glycerol-limited growth. 3. Small but significant signals attributable to the NADH dehydrogenase were detected in submitochondrial particles from sulphate-limited cells. 4. Measurements made on submitochondrial particles prepared from these and other phenotypically modified cells lead us to conclude that the presence of low-temperature e.p.r.-detectable iron-sulphur centres attributable to the NADH dehydrogenase are necessary but not sufficient for the coupling of ATP synthesis to the NADH dehydrogenase reaction in the mitochondrial membrane of C. utilis. 6. The amplitude of the g=2.01 signal observed in non-reduced submitochondrial particles is approximately tenfold diminished by iron limitation but not significantly altered by sulphate limitation.

scholarly journals Some magnetic properties of Pseudomonas cytochrome oxidase

1979 ◽  
Vol 177 (1) ◽  
pp. 29-39 ◽  
Author(s):  
T A Walsh ◽  
M K Johnson ◽  
C Greenwood ◽  
D Barber ◽  
J P Springall ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Cytochrome C ◽  
Cytochrome Oxidase ◽  
Magnetic Circular Dichroism ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Parallel Study ◽  
Paramagnetic Resonance ◽  
Redox States ◽  
Electron Paramagnetic

The magnetic properties of the haem groups of Pseudomonas cytochrome oxidase and its cyanide-bound derivatives were studied in both the oxidized and reduced states by means of m.c.d. (magnetic circular dichroism) at low temperatures. In addition, the oxidized forms of the enzyme were also investigated by e.p.r. (electron-paramagnetic-resonance) spectroscopy, and a parallel study, using both e.p.r. and m.c.d., was made on Pseudomonas cytochrome c-551 to aid spectral assignments. For ascorbate-reduced Pseudomonas cytochrome oxidase, the temperature-independence of those features in the m.c.d. spectrum corresponding to the haem c, and the temperature-dependence of those signals corresponding to the haem d1, showed the former to be low-spin and the latter to be high-spin (s = 2). However, addition of cyanide to the reduced enzyme gave a form of the protein that was completely low-spin. The e.p.r. and m.c.d. sectra of oxidized Pseudomonas cytochrome oxidase and its cyanide derivative were consistent with the haem c and d1 components being low-spin in both cases. Pseudomonas cytochrome c-551 was found to be low-spin in both its oxidized and reduced redox states.

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