Dataset Information

Molecular analysis of two genes of the Escherichia coli gab cluster: nucleotide sequence of the glutamate:succinic semialdehyde transaminase gene (gabT) and characterization of the succinic semialdehyde dehydrogenase gene (gabD).

ABSTRACT: We have characterized two genes of the Escherichia coli K-12 gab cluster, which encodes the enzymes of the 4-aminobutyrate degradation pathway. The nucleotide sequence of gabT, coding for glutamate:succinic semialdehyde transaminase (EC 2.6.1.19), alternatively known as 4-aminobutyrate transaminase, was determined. The structural gene consists of 1,281 nucleotides specifying a protein of 426 amino acids with a molecular mass of 45.76 kDa. The protein shows significant homologies to the ornithine transaminases from Saccharomyces cerevisiae and from rat and human mitochondria. Three functionally and structurally important amino acid residues of the transaminase were identified by sequence comparison studies, and evolutionary relationships of the aminotransferases are discussed. The gabD gene, encoding succinic semialdehyde dehydrogenase (EC 1.2.1.16), was cloned and shown to be located adjacent to the 5' end of gabT. Expression studies with subfragments of the initially cloned DNA region revealed a maximal size of 1.7 kb for gabD. Both genes are cotranscribed from a promoter located upstream of gabD.

SUBMITTER: Bartsch K

PROVIDER: S-EPMC210825 | biostudies-other | 1990 Dec

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

Molecular analysis of two genes of the Escherichia coli gab cluster: nucleotide sequence of the glutamate:succinic semialdehyde transaminase gene (gabT) and characterization of the succinic semialdehyde dehydrogenase gene (gabD).

Bartsch K K von Johnn-Marteville A A Schulz A A

Journal of bacteriology 19901201 12

We have characterized two genes of the Escherichia coli K-12 gab cluster, which encodes the enzymes of the 4-aminobutyrate degradation pathway. The nucleotide sequence of gabT, coding for glutamate:succinic semialdehyde transaminase (EC 2.6.1.19), alternatively known as 4-aminobutyrate transaminase, was determined. The structural gene consists of 1,281 nucleotides specifying a protein of 426 amino acids with a molecular mass of 45.76 kDa. The protein shows significant homologies to the ornithine ...[more]

PMID: 2254272

Similar Datasets

Project description:BackgroundBioenergetic characterisation of malignant tissues revealed that different tumour cells can catabolise multiple substrates as salvage pathways, in response to metabolic stress. Altered metabolism in gliomas has received a lot of attention, especially in relation to IDH mutations, and the associated oncometabolite D-2-hydroxyglutarate (2-HG) that impact on metabolism, epigenetics and redox status. Astrocytomas and oligodendrogliomas, collectively called diffuse gliomas, are derived from astrocytes and oligodendrocytes that are in metabolic symbiosis with neurons; astrocytes can catabolise neuron-derived glutamate and gamma-aminobutyric acid (GABA) for supporting and regulating neuronal functions.MethodsMetabolic characteristics of human glioma cell models - including mitochondrial function, glycolytic pathway and energy substrate oxidation - in relation to IDH mutation status and after 2-HG incubation were studied to understand the Janus-faced role of IDH1 mutations in the progression of gliomas/astrocytomas. The metabolic and bioenergetic features were identified in glioma cells using wild-type and genetically engineered IDH1-mutant glioblastoma cell lines by metabolic analyses with Seahorse, protein expression studies and liquid chromatography-mass spectrometry.ResultsU251 glioma cells were characterised by high levels of glutamine, glutamate and GABA oxidation. Succinic semialdehyde dehydrogenase (SSADH) expression was correlated to GABA oxidation. GABA addition to glioma cells increased proliferation rates. Expression of mutated IDH1 and treatment with 2-HG reduced glutamine and GABA oxidation, diminished the pro-proliferative effect of GABA in SSADH expressing cells. SSADH protein overexpression was found in almost all studied human cases with no significant association between SSADH expression and clinicopathological parameters (e.g. IDH mutation).ConclusionsOur findings demonstrate that SSADH expression may participate in the oxidation and/or consumption of GABA in gliomas, furthermore, GABA oxidation capacity may contribute to proliferation and worse prognosis of gliomas. Moreover, IDH mutation and 2-HG production inhibit GABA oxidation in glioma cells. Based on these data, GABA oxidation and SSADH activity could be additional therapeutic targets in gliomas/glioblastomas.

Dataset Information

Molecular analysis of two genes of the Escherichia coli gab cluster: nucleotide sequence of the glutamate:succinic semialdehyde transaminase gene (gabT) and characterization of the succinic semialdehyde dehydrogenase gene (gabD).

Publications

Molecular analysis of two genes of the Escherichia coli gab cluster: nucleotide sequence of the glutamate:succinic semialdehyde transaminase gene (gabT) and characterization of the succinic semialdehyde dehydrogenase gene (gabD).

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets