The coordinate regulation of multiple terminal oxidases by the Pseudomonas putida ANR global regulator.
Pseudomonas putida KT2440 contains a branched aerobic respiratory chain with multiple terminal oxidases. Their relative proportion varies according to environmental conditions. The role of the oxygen-responsive ANR global regulator on expression of these terminal oxidases was analysed. During exponential growth in a highly aerated complete medium, ANR activated expression of the Cbb3-1 terminal oxidase (equivalent to Pseudomonas aeruginosa Cbb3-2), but had little role on expression of other terminal oxidases. In early stationary phase, or under oxygen limitation, inactivation of the anr gene led to increased expression of the bo(3)-type cytochrome (Cyo) and cyanide-insensitive (CIO) terminal oxidases, and to a much lower expression of Cbb3-1. DNase I footprints identified ANR binding sites at the promoters for these oxidases. Their location suggests that ANR is a transcriptional activator of Cbb3-1 genes and a repressor of CIO genes, consistent with expression data. ANR binding sites at the promoter for Cyo genes suggests a complex regulation in combination with other factors. Therefore, ANR coordinates expression of Cyo, CIO and Cbb3-1, but does not influence cytochrome aa3 and Cbb3-2 terminal oxidases under the conditions analysed. Functional assays showed that Cyo has a leading role during aerobic exponential growth, while Cbb3-1 becomes very important in stationary phase.
Ugidos
Ana
A
Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Campus de la Universidad Autónoma de Madrid, Cantoblanco, 28049 - Madrid, Spain.
Morales
Gracia
G
Rial
Eduardo
E
Williams
Huw D
HD
Rojo
Fernando
F
D001426:Bacterial Proteins / Q000378:metabolism / Q000502:physiology*; D003576:Electron Transport Complex IV / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D005809:Genes, Regulator; D016958:Pseudomonas putida / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D015534:Trans-Activators / Q000378:metabolism / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology
D001426:Bacterial Proteins; D015534:Trans-Activators; D014157:Transcription Factors; C072908:ANR protein, Pseudomonas aeruginosa; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV