Molecular cloning and characterization of Escherichia coli K12 ygjG gene

Samsonova, Natalya N.; Smirnov, Sergey V.; Al'tman, I. B.; Ptitsyn, Leonid R.

doi:10.1186/1471-2180-3-2

Cited by 57 publications

(36 citation statements)

References 34 publications

(27 reference statements)

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“…A noteworthy property of PuuA is the extraordinarily high K m value for putrescine (44.6 mM). This high K m value is consistent with the high K m value (9.2 mM) for putrescine of His-tagged YgjG (putrescine:␣-ketoglutarate aminotransferase) of E. coli (13). The intracellular concentration of free putrescine in E. coli was reported previously to be significantly high (12 mM) (32).…”

Section: Discussionsupporting

confidence: 73%

“…Also regulation of the expression of puuA was not fully reported except that the regulation of puuA occurring in response to O 2 was mediated by ArcA and FNR (27). Furthermore experimental comparison of two putrescine degradation pathways in E. coli (9,10,12,13) (Fig. 2) has not been performed, and the similarity between GS and PuuA has not been discussed.…”

Section: Discussionmentioning

confidence: 99%

“…Two Putrescine Degradation Pathways to Yield GABAThere are two putrescine degradation pathways in E. coli: the Puu pathway (9) in which putrescine is first ␥-glutamylated and metabolized to GABA and the YgjG-YdcW pathway (11)(12)(13) in which putrescine is metabolized to GABA without ␥-glutamylation (Fig. 2).…”

Section: Discussionmentioning

confidence: 99%

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γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Kurihara

Oda

Tsuboi

et al. 2008

Journal of Biological Chemistry

110

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Glutamate-putrescine ligase (␥-glutamylputrescine synthetase, PuuA, EC 6.3.1.11) catalyzes the ␥-glutamylation of putrescine, the first step in a novel putrescine utilization pathway involving ␥-glutamylated intermediates, the Puu pathway, in Escherichia coli. In this report, the character and physiological importance of PuuA are described. Purified non-tagged PuuA catalyzed the ATP-dependent ␥-glutamylation of putrescine. The K m values for glutamate, ATP, and putrescine are 2.07, 2.35, and 44.6 mM, respectively. There are two putrescine utilization pathways in E. coli: the Puu pathway and the pathway without ␥-glutamylation. Gene deletion experiments of puuA, however, indicated that the Puu pathway was more critical in utilizing putrescine as a sole carbon or nitrogen source. The transcription of puuA was induced by putrescine and in a puuR-deleted strain. The amino acid sequences of PuuA and glutamine synthetase (GS) show high similarity. The molecular weights of the monomers of the two enzymes are quite similar, and PuuA exists as a dodecamer as does GS. Moreover the two amino acid residues of E. coli GS that are important for the metal-catalyzed oxidation of the enzyme molecule involved in protein turnover are conserved in PuuA, and it was experimentally shown that the corresponding amino acid residues in PuuA were involved in the metal-catalyzed oxidation similarly to GS. It is suggested that the intracellular concentration of putrescine is optimized by PuuA transcriptionally and posttranslationally and that excess putrescine is converted to a nutrient source by the Puu pathway.

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Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 99%

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γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Kurihara

Oda

Tsuboi

et al. 2008

Journal of Biological Chemistry

110

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“…glnHPQ codes for components of a high affinity glutamine transport system (43,44); nac for a regulator of several Ntr genes (44); and ygjG for putrescine transaminase (45,46). The promoters for these operons, except for glnA-ntrBC, were fused to lacZ and expressed on the chromosome.…”

Section: Alteration Of Surface Residues Of the B-helix Of The C-terminalmentioning

confidence: 99%

Phosphorylation-independent Dimer-Dimer Interactions by the Enhancer-binding Activator NtrC of Escherichia coli

Yang

Schneider³

et al. 2004

Journal of Biological Chemistry

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The response regulator NtrC transcriptionally activates genes of the nitrogen-regulated (Ntr) response. Phosphorylation of its N-terminal receiver domain stimulates an essential oligomerization of the central domain. Deletion of the central domain reduces, but does not eliminate, intermolecular interactions as assessed by cooperative binding to DNA. To analyze the structural determinants and function of this central domain-independent as well as phosphorylation-independent oligomerization, we randomly mutagenized DNA coding for an NtrC without its central domain and isolated strains containing NtrC with defective phosphorylation-independent cooperative binding. The alterations were primarily localized to helix B of the C-terminal domain. Site-specific mutagenesis that altered surface residues of helix B confirmed this localization. The purified NtrC variants, with or without the central domain, were specifically defective in phosphorylation-independent cooperative DNA binding and had little defect, if any, on other functions, such as noncooperative DNA binding. We propose that this region forms an oligomerization interface. Full-length NtrC variants did not efficiently repress the glnA-ntrBC operon when NtrC was not phosphorylated, which suggests that phosphorylation-independent cooperative binding sets the basal level for glutamine synthetase and the regulators of the Ntr response. The NtrC variants in these cells generally, but not always, supported wild-type growth in nitrogen-limited media and wild-type activation of a variety of Ntr genes. We discuss the differences and similarities between the NtrC C-terminal domain and the homologous Fis, which is also capable of intermolecular interactions.

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“…The Puu pathway metabolizes putrescine via ␥-glutamylated intermediates and ␥-amino butyric acid (GABA) to succinic semialdehyde, a precursor of succinate (7). The YgjG-YdcW pathway metabolizes putrescine to GABA without ␥-glutamylation (18,19). The Puu pathway is thought to be the main putrescine utilization pathway.…”

mentioning

confidence: 99%

Mechanism for Regulation of the Putrescine Utilization Pathway by the Transcription Factor PuuR in Escherichia coli K-12

et al. 2012

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bIn Escherichia coli, putrescine is metabolized to succinate for use as a carbon and nitrogen source by the putrescine utilization pathway (Puu pathway). One gene in the puu gene cluster encodes a transcription factor, PuuR, which has a helix-turn-helix DNA-binding motif. DNA microarray analysis of an E. coli puuR mutant, in which three amino acid residues in the helix-turnhelix DNA binding motif of PuuR were mutated to alanine to eliminate DNA binding of PuuR, suggested that PuuR is a negative regulator of puu genes. Results of gel shift and DNase I footprint analyses suggested that PuuR binds to the promoter regions of puuA and puuD. The binding of wild-type PuuR to a DNA probe containing PuuR recognition sites was diminished with increasing putrescine concentrations in vitro. These results suggest that PuuR regulates the intracellular putrescine concentration by the transcriptional regulation of genes in the Puu pathway, including puuR itself. The puu gene cluster is found in E. coli and closely related enterobacteria, but this gene cluster is uncommon in other bacterial groups. E. coli and related enterobacteria may have gained the Puu pathway as an adaptation for survival in the mammalian intestine, an environment in which polyamines exist at relatively high concentrations.

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Molecular cloning and characterization of Escherichia coli K12 ygjG gene

Cited by 57 publications

References 34 publications

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

γ-Glutamylputrescine Synthetase in the Putrescine Utilization Pathway of Escherichia coli K-12

Phosphorylation-independent Dimer-Dimer Interactions by the Enhancer-binding Activator NtrC of Escherichia coli

Mechanism for Regulation of the Putrescine Utilization Pathway by the Transcription Factor PuuR in Escherichia coli K-12

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