Reduction of clofazimine by mycobacterial type 2 NADH:quinone oxidoreductase: a pathway for the generation of bactericidal levels of reactive oxygen species.
J Biol Chem
; 286(12): 10276-87, 2011 Mar 25.
Article
em En
| MEDLINE
| ID: mdl-21193400
ABSTRACT
The mechanism of action of clofazimine (CFZ), an antimycobacterial drug with a long history, is not well understood. The present study describes a redox cycling pathway that involves the enzymatic reduction of CFZ by NDH-2, the primary respiratory chain NADHquinone oxidoreductase of mycobacteria and nonenzymatic oxidation of reduced CFZ by O(2) yielding CFZ and reactive oxygen species (ROS). This pathway was demonstrated using isolated membranes and purified recombinant NDH-2. The reduction and oxidation of CFZ was measured spectrally, and the production of ROS was measured using a coupled assay system with Amplex Red. Supporting the ROS-based killing mechanism, bacteria grown in the presence of antioxidants are more resistant to CFZ. CFZ-mediated increase in NADH oxidation and ROS production were not observed in membranes from three different Gram-negative bacteria but was observed in Staphylococcus aureus and Saccharomyces cerevisiae, which is consistent with the known antimicrobial specificity of CFZ. A more soluble analog of CFZ, KS6, was synthesized and was shown to have the same activities as CFZ. These studies describe a pathway for a continuous and high rate of reactive oxygen species production in Mycobacterium smegmatis treated with CFZ and a CFZ analog as well as evidence that cell death produced by these agents are related to the production of these radical species.
Texto completo:
1
Tema:
Epidemiologia
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Geral
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Tratamento_medicamentoso
Bases de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
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NAD(P)H Desidrogenase (Quinona)
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Clofazimina
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Espécies Reativas de Oxigênio
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Mycobacterium smegmatis
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Hansenostáticos
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2011
Tipo de documento:
Article