title: Three Pseudomonas putida FNR Family Proteins with Different Sensitivities to O2.
abstract: The Escherichia coli fumarate-nitrate reduction regulator (FNR) protein is the paradigm for bacterial O2-sensing transcription factors. However, unlike E. coli, some bacterial species possess multiple FNR proteins that presumably have evolved to fulfill distinct roles. Here, three FNR proteins (ANR, PP_3233, and PP_3287) from a single bacterial species, Pseudomonas putida KT2440, have been analyzed. Under anaerobic conditions, all three proteins had spectral properties resembling those of [4Fe-4S] proteins. The reactivity of the ANR [4Fe-4S] cluster with O2 was similar to that of E. coli FNR, and during conversion to the apo-protein, via a [2Fe-2S] intermediate, cluster sulfur was retained. Like ANR, reconstituted PP_3233 and PP_3287 were converted to [2Fe-2S] forms when exposed to O2, but their [4Fe-4S] clusters reacted more slowly. Transcription from an FNR-dependent promoter with a consensus FNR-binding site in P. putida and E. coli strains expressing only one FNR protein was consistent with the in vitro responses to O2. Taken together, the experimental results suggest that the local environments of the iron-sulfur clusters in the different P. putida FNR proteins influence their reactivity with O2, such that ANR resembles E. coli FNR and is highly responsive to low concentrations of O2, whereas PP_3233 and PP_3287 have evolved to be less sensitive to O2.
authors.affiliation: From the Krebs Institute, Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Susan A
authors.initials: SA
authors.lastname: Ibrahim
authors.affiliation: the Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, United Kingdom, and.
authors.forename: Jason C
authors.initials: JC
authors.lastname: Crack
authors.affiliation: From the Krebs Institute, Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Rolfe
authors.affiliation: Institut für Mikrobiologie, Technische Universität, D-38106 Braunschweig, Germany.
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Borrero-de Acuña
authors.affiliation: the Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, United Kingdom, and.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Thomson
authors.affiliation: the Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, United Kingdom, and.
authors.forename: Nick E
authors.initials: NE
authors.lastname: Le Brun
authors.affiliation: Institut für Mikrobiologie, Technische Universität, D-38106 Braunschweig, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Schobert
authors.affiliation: From the Krebs Institute, Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom.
authors.forename: Melanie R
authors.initials: MR
authors.lastname: Stapleton
authors.affiliation: From the Krebs Institute, Molecular Biology and Biotechnology, University of Sheffield, Sheffield, S10 2TN, United Kingdom, jeff.green@sheffield.ac.uk.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Green
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005810:Multigene Family; D010100:Oxygen / Q000378:metabolism*; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; D010100:Oxygen
keywords: bacterial signal transduction; bacterial transcription; iron-sulfur protein; microbiology; transcription factor; transcription regulation