FTIR-monitored thermal titration reveals different mechanisms for the alkaline isomerization of tuna compared to horse and bovine cytochromes c

1999 ◽  
Vol 4 (6) ◽  
pp. 717-726
Author(s):  
Angelo Filosa ◽  
A. A. Ismail ◽  
A. M. English
1975 ◽  
Vol 149 (1) ◽  
pp. 155-167 ◽  
Author(s):  
G W Pettigrew ◽  
I Aviram ◽  
A Schejter

Cytochrome c-557 from Crithidia oncopelti and cytochrome c-558 from Euglena gracilis are mitochondrial cytochromes c that have an atypical haem-binding site. It was of interest to know whether the loss of one thioether bond affected the physicochemical properties of these cytochromes. The thermodynamic parameters of the redox potential were measured. The reaction with imidazole, the kinetics and thermodynamics of the alkaline isomerization and the effect of heating on the visible spectrum are described for the ferricytochromes. The kinetics of the loss of cyanide, the spectral changes occurring on reduction with dithionite at alkaline pH values and the reactivity with CO are described for the ferrocytochromes. In many respects the cytochromes of the two protozoans are very similar to the cytochromes of horse and yeast. The ferricytochromes do, however, undergo a reversible transition to high-spin species on heating, which may be due to the more flexible attachment of the prosthetic group. Similarly the alkaline isomers of cytochromes c-557 and c-558 give rise to high-spin proteins above pH 11. The alkaline isomerization of cytochrome c-558, involves a pKobs. of 10 and kinetics which do not obey the model of Davis et al. [(1974) J. Biol. Chem.249, 2624-2632] for horse cytochrome c. It is proposed that a model involving two ionizations, followed by a conformation change, may fit the data. Both cytochromes c-557 and c-558 combine slowly with CO at neutral pH values.


2009 ◽  
Vol 12 (5) ◽  
pp. 233-236 ◽  
Author(s):  
Yvan Looze ◽  
Enrico Polastro ◽  
Marc Deconinck ◽  
Jose Leonis

1979 ◽  
Vol 254 (23) ◽  
pp. 11973-11981 ◽  
Author(s):  
J.K. Dethmers ◽  
S. Ferguson-Miller ◽  
E. Margoliash
Keyword(s):  

1977 ◽  
Vol 252 (2) ◽  
pp. 574-582 ◽  
Author(s):  
D L Brautigan ◽  
B A Feinberg ◽  
B M Hoffman ◽  
E Margoliash ◽  
J Preisach ◽  
...  

Extremophiles ◽  
2014 ◽  
Vol 18 (3) ◽  
pp. 617-627 ◽  
Author(s):  
Misa Masanari ◽  
Satoshi Wakai ◽  
Manabu Ishida ◽  
Chiaki Kato ◽  
Yoshihiro Sambongi

2001 ◽  
Vol 67 (7) ◽  
pp. 3236-3244 ◽  
Author(s):  
A. I. Tsapin ◽  
I. Vandenberghe ◽  
K. H. Nealson ◽  
J. H. Scott ◽  
T. E. Meyer ◽  
...  

ABSTRACT Two abundant, low-redox-potential cytochromesc were purified from the facultative anaerobeShewanella oneidensis strain MR1 grown anaerobically with fumarate. The small cytochrome was completely sequenced, and the genes coding for both proteins were cloned and sequenced. The small cytochrome c contains 91 residues and four heme binding sites. It is most similar to the cytochromes c fromShewanella frigidimarina (formerly Shewanella putrefaciens) NCIMB400 and the unclassified bacterial strain H1R (64 and 55% identity, respectively). The amount of the small tetraheme cytochrome is regulated by anaerobiosis, but not by fumarate. The larger of the two low-potential cytochromes contains tetraheme and flavin domains and is regulated by anaerobiosis and by fumarate and thus most nearly corresponds to the flavocytochromec-fumarate reductase previously characterized fromS. frigidimarina to which it is 59% identical. However, the genetic context of the cytochrome genes is not the same for the twoShewanella species, and they are not located in multicistronic operons. The small cytochrome c and the cytochrome domain of the flavocytochrome c are also homologous, showing 34% identity. Structural comparison shows that theShewanella tetraheme cytochromes are not related to theDesulfovibrio cytochromes c 3but define a new folding motif for small multiheme cytochromesc.


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