| Título: | Apparent redundancy of electron transfer pathways via bc(1) complexes and terminal oxidases in the extremophilic chemolithoautotrophic Acidithiobacillus ferrooxidans |
| Autores: |
Brasseur, G. Levicán, Gloria Bonnefoy, Violaine Holmes, David S. Jedlicki C., Eugenia María Lemesle Meunier, D. |
| Fecha: |
2007-04-18 2007-04-18 2004-06-07 |
| Publicador: | ELSEVIER |
| Fuente: |
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| Tipo: | Artículo de Revista |
| Tema: |
CYTOCHROME-C-OXIDASE BACTERIUM THIOBACILLUS-FERROOXIDANS BLUE COPPER PROTEIN THERMUS-THERMOPHILUS OXIDIZING BACTERIUM RESPIRATORY-CHAIN ESCHERICHIA-COLI QUINOL OXIDASE PARACOCCUS-DENITRIFICANS SPECTROSCOPIC PROPERTIES |
| Descripción: | Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotrophic bacterium that can grow in the presence of either the weak reductant Fe2+, or reducing sulfur compounds that provide more energy for growth than Fe2+. We have previously shown that the uphill electron transfer pathway between Fe2+ and NAD(+) involved a bc(1) complex that functions only in the reverse direction [J. Bacteriol. 182, (2000) 3602]. In the present work, we demonstrate both the existence of a bc(1) complex functioning in the forward direction, expressed when the cells are grown on sulfur, and the presence of two terminal oxidases, a bd and a ba(3) type oxidase expressed more in sulfur than in iron-grown cells, besides the cytochrome aa(3) that was found to be expressed only in iron-grown cells. Sulfur-grown cells exhibit a branching point for electron flow at the level of the quinol pool leading on the one hand to a bd type oxidase, and on the other hand to a bc(1) --> ba(3) pathway. We have also demonstrated the presence in the genome of transcriptionally active genes potentially encoding the subunits of a bo(3) type oxidase. A scheme for the electron transfer chains has been established that shows the existence of multiple respiratory routes to a single electron acceptor O-2. Possible reasons for these apparently redundant pathways are discussed. |
| Idioma: | Inglés |