Bacterial degradation of benzoate: cross-regulation between aerobic and anaerobic pathways.
We have studied for the first time the transcriptional regulatory circuit that controls the expression of the box genes encoding the aerobic hybrid pathway used to assimilate benzoate via coenzyme A (CoA) derivatives in bacteria. The promoters responsible for the expression of the box cluster in the β-proteobacterium Azoarcus sp., their cognate transcriptional repressor, the BoxR protein, and the inducer molecule (benzoyl-CoA) have been characterized. The BoxR protein shows a significant sequence identity to the BzdR transcriptional repressor that controls the bzd genes involved in the anaerobic degradation of benzoate. Because the boxR gene is present in all box clusters so far identified in bacteria, the BoxR/benzoyl-CoA regulatory system appears to be a widespread strategy to control this aerobic hybrid pathway. Interestingly, the paralogous BoxR and BzdR regulators act synergistically to control the expression of the box and bzd genes. This cross-regulation between anaerobic and aerobic pathways for the catabolism of aromatic compounds has never been shown before, and it may reflect a biological strategy to increase the cell fitness in organisms that survive in environments subject to changing oxygen concentrations.
Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
J Andrés
JA
Valderrama
Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
Gonzalo
G
Durante-Rodríguez
Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
Blas
B
Blázquez
Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
José Luis
JL
García
Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain.
Manuel
M
Carmona
Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, 28040 Madrid, Spain. Electronic address: ediaz@cib.csic.es.
Eduardo
E
Díaz
D000332:Aerobiosis / Q000187:drug effects / Q000502:physiology; D000693:Anaerobiosis / Q000187:drug effects / Q000502:physiology; D000890:Anti-Infective Agents / Q000378:metabolism / Q000494:pharmacology; D020627:Azoarcus / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001565:Benzoates / Q000378:metabolism* / Q000494:pharmacology; D003065:Coenzyme A / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*
D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D001565:Benzoates; D012097:Repressor Proteins; D003065:Coenzyme A