ISSN:
1573-6881
Keywords:
Cytochromebc 1 complex
;
ubiquinol oxidation
;
ubiquinone reduction
;
electron transport
;
Rhodobacter capsulatus
;
photosynthetic bacteria
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
,
Physics
Notes:
Abstract The cytochromebc 1 complexes from the nonphotosynthetic strain R126 ofRhodobacter capsulatus and from its revertant MR126 were purified. Between both preparations, no difference could be observed in the stoichiometries of the cytochromes, in their spectral properties, and in their midpoint redox potentials. Both also showed identical polypeptide patterns after electrophoresis on polyacrylamide gels in the presence of sodium dodecylsulfate. The ubiquinol: cytochromec oxidoreductase activity was strongly inhibited in the complex from the mutant compared to the one from the revertant. So was the oxidant-induced extra reduction of cytochromeb. Both preparations, however, showed an antimycin-induced red shift of cytochromeb, as well as antimycin-sensitive reduction of cytochromeb by ubiquinol. In accordance with a preceding study of chromatophores (Robertsonet al. (1986).J. Biol. Chem. 261, 584–591), it is concluded that the mutation affects specifically the ubiquinol oxidizing site, leaving the ubiquinol reducing site unchanged.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00762228
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