title: Unraveling the specific regulation of the central pathway for anaerobic degradation of 3-methylbenzoate.
abstract: The mbd cluster encodes the anaerobic degradation of 3-methylbenzoate in the β-proteobacterium Azoarcus sp. CIB. The specific transcriptional regulation circuit that controls the expression of the mbd genes was investigated. The PO, PB 1, and P3 R promoters responsible for the expression of the mbd genes, their cognate MbdR transcriptional repressor, as well as the MbdR operator regions (ATACN10GTAT) have been characterized. The three-dimensional structure of MbdR has been solved revealing a conformation similar to that of other TetR family transcriptional regulators. The first intermediate of the catabolic pathway, i.e. 3-methylbenzoyl-CoA, was shown to act as the inducer molecule. An additional MbdR-dependent promoter, PA, which contributes to the expression of the CoA ligase that activates 3-methylbenzoate to 3-methylbenzoyl-CoA, was shown to be necessary for an efficient induction of the mbd genes. Our results suggest that the mbd cluster recruited a regulatory system based on the MbdR regulator and its target promoters to evolve a distinct central catabolic pathway that is only expressed for the anaerobic degradation of aromatic compounds that generate 3-methylbenzoyl-CoA as the central metabolite. All these results highlight the importance of the regulatory systems in the evolution and adaptation of bacteria to the anaerobic degradation of aromatic compounds.
authors: From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors: Javier F
authors: JF
authors: Juárez
authors: the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and.
authors: Huixiang
authors: H
authors: Liu
authors: From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors: María T
authors: MT
authors: Zamarro
authors: the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and.
authors: Stephen
authors: S
authors: McMahon
authors: the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and.
authors: Huanting
authors: H
authors: Liu
authors: the Biomedical Sciences Research Complex, University of St. Andrews, North Haugh, St. Andrews KY16 9ST, Scotland, United Kingdom, and.
authors: James H
authors: JH
authors: Naismith
authors: the Institute for Biology II, University of Freiburg, 79104 Freiburg, Germany.
authors: Christian
authors: C
authors: Eberlein
authors: the Institute for Biology II, University of Freiburg, 79104 Freiburg, Germany.
authors: Matthias
authors: M
authors: Boll
authors: From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain.
authors: Manuel
authors: M
authors: Carmona
authors: From the Department of Environmental Biology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid, Spain, ediaz@cib.csic.es.
authors: Eduardo
authors: E
authors: Díaz
mesh_terms: D000595:Amino Acid Sequence; D000693:Anaerobiosis; D020627:Azoarcus / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry*; D001565:Benzoates / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D003850:Deoxyribonuclease I / Q000737:chemistry; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D007763:Lac Operon; D008958:Models, Molecular; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D009841:Oligonucleotides / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D012097:Repressor Proteins / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014461:Ultracentrifugation; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D001565:Benzoates; D009841:Oligonucleotides; D012097:Repressor Proteins; C044605:methyl benzoate; D004247:DNA; D003850:Deoxyribonuclease I; D001616:beta-Galactosidase
keywords: 3-Methylbenzoate; Anaerobic Degradation; Azoarcus; Bacterial Transcription; Gene Expression; Microbiology; Protein-DNA Interaction; Transcription Regulation