Expression of the
            <i>Azotobacter vinelandii</i>
            Poly-β-Hydroxybutyrate Biosynthetic
            <i>phbBAC</i>
            Operon Is Driven by Two Overlapping Promoters and Is Dependent on the Transcriptional Activator PhbR

Peralta-Gil, Martín; Segura, Daniel; Guzmán, Josefina; Servı́n‐González, Luis; Espı́n, Guadalupe

doi:10.1128/jb.184.20.5672-5677.2002

Cited by 72 publications

(78 citation statements)

References 28 publications

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“…1, alginate is synthesized from fructose 6-phosphate by many enzymes encoded by the alg cluster, 8,15 whereas PHB is synthesized in 3 steps from acetyl-CoA and 3 phb genes are essential for synthesis. 16 The regulatory mechanisms for the production of these biopolymers have been analyzed. [16][17][18][19][20][21][22][23][24][25] Thus, the biopolymers are expected to be produced from excess and/or unused resource by A. vinelandii.…”

Section: Introductionmentioning

confidence: 99%

Production of polyhydroxybutyrate and alginate from glycerol byAzotobacter vinelandiiunder nitrogen-free conditions

et al. 2015

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Glycerol is an interesting feedstock for biomaterials such as biofuels and bioplastics because of its abundance as a by-product during biodiesel production. Here we demonstrate glycerol metabolism in the nitrogen-fixing species Azotobacter vinelandii through metabolomics and nitrogen-free bacterial production of biopolymers, such as poly-D-3-hydroxybutyrate (PHB) and alginate, from glycerol. Glycerol-3-phosphate was accumulated in A. vinelandii cells grown on glycerol to the exponential phase, and its level drastically decreased in the cells grown to the stationary growth phase. A. vinelandii also overexpressed the glycerol-3-phosphate dehydrogenase gene when it was grown on glycerol. These results indicate that glycerol was first converted to glycerol-3-phosphate by glycerol kinase. Other molecules with industrial interests, such as lactic acid and amino acids including g-aminobutyric acid, have also been accumulated in the bacterial cells grown on glycerol. Transmission electron microscopy revealed that glycerol-grown A. vinelandii stored PHB within the cells. The PHB production level reached 33% per dry cell weight in nitrogen-free glycerol medium. When grown on glycerol, alginate-overproducing mutants generated through chemical mutagenesis produced 2-fold the amount of alginate from glycerol than the parental wild-type strain. To the best of our knowledge, this is the first report on bacterial production of biopolymers from glycerol without addition of any nitrogen source.

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Section: Introductionmentioning

confidence: 99%

Production of polyhydroxybutyrate and alginate from glycerol byAzotobacter vinelandiiunder nitrogen-free conditions

et al. 2015

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“…There have recently been reports that PHB genes have high sequence difference in different strains (Peralta-Gil et al, 2002). In the present study, we report on the identification and molecular characterization of phbA, phbB and phbC, three genes whose nucleic acid sequence contains some singlenucleotide polymorphisms and indels compared to formerly cloned genes.…”

Section: Discussionmentioning

confidence: 97%

Molecular and functional analysis of the poly-β-hydroxybutyrate biosynthesis operon of Pseudomonas sp BJ-1

Zhu¹,

Zhang²,

Jiang³

et al. 2010

Genet. Mol. Res.

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ABSTRACT. The operon comprising the genes for poly-β-hydroxybutyrate (PHB) biosynthesis in Pseudomonas sp BJ-1 was cloned and sequenced. Sequence analysis of 8991 bp revealed that the regions contain two related operons. The first operon contains the three genes phbA, phbB and phbC, and the other contains the two genes flp1 and flp2. The deduced amino acid sequences of PHBA and PHBB showed high identity with other bacterial PHB genes. Transcription of the three genes of the first operon is controlled by a single hypothetical promoter region, whereas the other two flp genes are controlled by two hypothetical promoter regions. Analysis of expressed protein at different times showed that PHBA protein levels increased from 0 to 4 h; PHBB and PHBC showed similar kinetics. Detection of enzyme activity showed three proteins with bioactivity and biological function in the synthesis of PHB intermediates.

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“…The phbR gene, located upstream and in the opposite direction to phbB, encodes a transcriptional activator of the AraC family, and a mutation in phbR reduces accumulation of PHB (PeraltaGil et al, 2002). Transcription of the phbBAC gene cluster has been shown to start from two overlapping promoters, p B 1 and p B 2, and a reduction in the transcription of phbB from its p B 1 promoter in the phbR mutant has been revealed in an S1-mapping experiment (Peralta-Gil et al, 2002). A consensus sequence recognized by RpoS is present in p B 2 (Peralta-Gil et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Thus, R1 and R2 have been proposed to be PhbR-binding sites. Four other less conserved 18 bp sequences, designated R3, R4, R5 and R6, have also been identified within the intergenic phbR-phbB region (Peralta-Gil et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

“…Transcription of the phbBAC gene cluster has been shown to start from two overlapping promoters, p B 1 and p B 2, and a reduction in the transcription of phbB from its p B 1 promoter in the phbR mutant has been revealed in an S1-mapping experiment (Peralta-Gil et al, 2002). A consensus sequence recognized by RpoS is present in p B 2 (Peralta-Gil et al, 2002). Two start sites for the transcription of phbR have also been identified, defining the p R 1 and p R 2 promoters.…”

Section: Introductionmentioning

confidence: 99%

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Transcriptional activation of the Azotobacter vinelandii polyhydroxybutyrate biosynthetic genes phbBAC by PhbR and RpoS

et al. 2011

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We previously showed that in Azotobacter vinelandii, accumulation of polyhydroxybutyrate (PHB) occurs mainly during the stationary phase, and that a mutation in phbR, encoding a transcriptional regulator of the AraC family, reduces PHB accumulation. In this study, we characterized the roles of PhbR and RpoS, a central regulator during stationary phase in bacteria, in the regulation of expression of the PHB biosynthetic operon phbBAC and phbR. We showed that inactivation of rpoS reduced PHB accumulation, similar to the phbR mutation, and inactivation of both rpoS and phbR resulted in an inability to produce PHB. We carried out expression studies with the wildtype, and the rpoS, phbR and double rpoS-phbR mutant strains, using quantitative RT-PCR, as well as phbB : : gusA and phbR : : gusA gene fusions. These studies showed that both PhbR and RpoS act as activators of phbB and phbR, and revealed a role for PhbR as an autoactivator. We also demonstrated that PhbR binds specifically to two almost identical 18 bp sites, TGTCACCAA -N 4 -CACTA and TGTCACCAA-N 4 -CAGTA, present in the phbB promoter region. The activation of phbB and phbR transcription by RpoS reported here is in agreement with the observation that accumulation of PHB in A. vinelandii occurs mainly during the stationary phase.

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Expression of the Azotobacter vinelandii Poly-β-Hydroxybutyrate Biosynthetic phbBAC Operon Is Driven by Two Overlapping Promoters and Is Dependent on the Transcriptional Activator PhbR

Cited by 72 publications

References 28 publications

Production of polyhydroxybutyrate and alginate from glycerol byAzotobacter vinelandiiunder nitrogen-free conditions

Production of polyhydroxybutyrate and alginate from glycerol byAzotobacter vinelandiiunder nitrogen-free conditions

Molecular and functional analysis of the poly-β-hydroxybutyrate biosynthesis operon of Pseudomonas sp BJ-1

Transcriptional activation of the Azotobacter vinelandii polyhydroxybutyrate biosynthetic genes phbBAC by PhbR and RpoS

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