The metabolism of 4-aminobutyrate (GABA) in fungi

Kumar, Santosh; Punekar, N. S.

doi:10.1017/s0953756296002742

Cited by 86 publications

(72 citation statements)

References 50 publications

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“…1. Smaller amounts of oxoglutarate formed after decarboxylation of isocitrate by IDH [2] may be bypassed to succinate via glutamate and ␥-aminobutyrate route as a minor pathway, as found in other bacteria (38,39) and fungi (28,40,41).…”

Section: Resultsmentioning

confidence: 99%

A physiological role for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris

Munir

Yoon

Tokimatsu

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

149

112

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A metabolic mechanism for oxalic acid biosynthesis in the woodrotting basidiomycete Fomitopsis palustris has been proposed on the basis of biochemical analyses of glucose metabolism. There was a strong correlation between glucose consumption and oxalate production. Oxalic acid was found to accumulate in the culture fluid in about 80% of the theoretical yield or about 5-fold, on the basis of the fungal biomass harvested. The results clearly indicate that glucose was not completely oxidized to CO2 by the tricarboxylic acid (TCA) cycle but converted mainly to oxalate. The determination of the 12 enzymes concerned has revealed the occurrence of the unprecedented metabolic coupling of the TCA and glyoxylate cycles that support oxalate biosynthesis. In this metabolic system, isocitrate lyase (EC 4.1.3.1), together with oxaloacetase (EC 3.7.1.1), was found to play a pivotal role in yielding oxalate from oxaloacetate via the acetate-recycling routes. Moreover, malate dehydrogenase (EC 1.1.1.37), with an extraordinarily high activity among the enzymes tested, was shown to play an important role in generating NADH by oxidation of malate to oxaloacetate. Thus, it is proposed that the wood-rotting basidiomycete acquires biochemical energy by oxidizing glucose to oxalate.

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Section: Resultsmentioning

confidence: 99%

A physiological role for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris

Munir

Yoon

Tokimatsu

et al. 2001

Proc. Natl. Acad. Sci. U.S.A.

149

112

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“…Published Aspergillus genomes do contain a putative agmatinase sequence(s) ( Table 1), but none has been functionally annotated. Putrescine in fungi either can form spermidine/spermine or is converted to 4-aminobutyrate (GABA) via 4-aminobutyraldehyde (GABald) (14,15). Another route to form putrescine from agmatine occurs in plants and archaebacteria; this involves two enzymes, namely, agmatine deiminase and N-carbamyl-putrescine hydrolase (16,17).…”

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confidence: 99%

“…GB could be used as the sole nitrogen source by Penicillium roqueforti (22,23) and K. lactis but not by S. cerevisiae (11). Finally, fungal GABA metabolism feeds into the Krebs cycle at succinate (15).…”

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confidence: 99%

Novel Route for Agmatine Catabolism in Aspergillus niger Involves 4-Guanidinobutyrase

Kumar¹,

Saragadam²,

Punekar³

2015

Appl Environ Microbiol

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Agmatine, a significant polyamine in bacteria and plants, mostly arises from the decarboxylation of arginine. The functional importance of agmatine in fungi is poorly understood. The metabolism of agmatine and related guanidinium group-containing compounds in Aspergillus niger was explored through growth, metabolite, and enzyme studies. The fungus was able to metabolize and grow on L-arginine, agmatine, or 4-guanidinobutyrate as the sole nitrogen source. Whereas arginase defined the only route for arginine catabolism, biochemical and bioinformatics approaches suggested the absence of arginine decarboxylase in A. niger. Efficient utilization by the parent strain and also by its arginase knockout implied an arginase-independent catabolic route for agmatine. Urea and 4-guanidinobutyrate were detected in the spent medium during growth on agmatine. The agmatinegrown A. niger mycelia contained significant levels of amine oxidase, 4-guanidinobutyraldehyde dehydrogenase, 4-guanidinobutyrase (GBase), and succinic semialdehyde dehydrogenase, but no agmatinase activity was detected. Taken together, the results support a novel route for agmatine utilization in A. niger. The catabolism of agmatine by way of 4-guanidinobutyrate to 4-aminobutyrate into the Krebs cycle is the first report of such a pathway in any organism. A. niger GBase peptide fragments were identified by tandem mass spectrometry analysis. The corresponding open reading frame from the A. niger NCIM 565 genome was located and cloned. Subsequent expression of GBase in both Escherichia coli and A. niger along with its disruption in A. niger functionally defined the GBase locus (gbu) in the A. niger genome.

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“…With the exception of the general amino acid permease Bra RI from Rhizobium leguminosarum, which belongs to the ATP binding cassette (ABC) transporters, GABA uptake in Gram-negative and Gram-positive bacteria as well as in Saccharomyces cerevisiae is mediated by members of the APC (amino acid/polyamine/organocation) superfamily of transporters (5,6). In both bacteria and yeast, GABA uptake and biosynthesis are mainly involved in nitrogen and carbon metabolism (7)(8)(9), although other functions such as GABA synthesis for pH regulation in Escherichia coli and for normal oxidative stress tolerance in S. cerevisiae have also been postulated (10,11).…”

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confidence: 99%

AtGAT1, a High Affinity Transporter for γ-Aminobutyric Acid in Arabidopsis thaliana

Meyer

Eskandari

Grallath

et al. 2006

Journal of Biological Chemistry

133

112

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Functional characterization of Arabidopsis thaliana GAT1 in heterologous expression systems, i.e. Saccharomyces cerevisiae and Xenopus laevis oocytes, revealed that AtGAT1 (At1g08230) codes for an H ؉ -driven, high affinity ␥-aminobutyric acid (GABA) transporter. In addition to GABA, other -aminofatty acids and butylamine are recognized. In contrast to the most closely related proteins of the proline transporter family, proline and glycine betaine are not transported by AtGAT1. AtGAT1 does not share sequence similarity with any of the non-plant GABA transporters described so far, and analyses of substrate selectivity and kinetic properties showed that AtGAT1-mediated transport is similar but distinct from that of mammalian, bacterial, and S. cerevisiae GABA transporters. Consistent with a role in GABA uptake into cells, transient expression of AtGAT1/green fluorescent protein fusion proteins in tobacco protoplasts revealed localization at the plasma membrane. In planta, AtGAT1 expression was highest in flowers and under conditions of elevated GABA concentrations such as wounding or senescence. ␥-Aminobutyric acid (GABA)3 is a four-carbon non-protein amino acid present in prokaryotes and eukaryotes. Although GABA was discovered in 1949 as a constituent of potato tubers, research on GABA metabolism and transport advanced much faster in the animal system as GABA turned out to be the most abundant inhibitory neurotransmitter in the central nervous system (1). Uptake of GABA into neurons and glia has been investigated in detail and shown to be mediated by Na ϩ -dependent and Cl Ϫ -facilitated GABA transporters (GATs), thus regulating concentration and duration of the neurotransmitter GABA in the synapse (2, 3). In addition to its function as a neurotransmitter, GABA plays a role in the development of the nervous system, influencing proliferation, migration, and differentiation (4). With the exception of the general amino acid permease Bra RI from Rhizobium leguminosarum, which belongs to the ATP binding cassette (ABC) transporters, GABA uptake in Gram-negative and Gram-positive bacteria as well as in Saccharomyces cerevisiae is mediated by members of the APC (amino acid/polyamine/organocation) superfamily of transporters (5, 6). In both bacteria and yeast, GABA uptake and biosynthesis are mainly involved in nitrogen and carbon metabolism (7-9), although other functions such as GABA synthesis for pH regulation in Escherichia coli and for normal oxidative stress tolerance in S. cerevisiae have also been postulated (10, 11).Much less is known about the role of GABA and its transport across the plasma membrane in plants. GABA rapidly accumulates under various stress conditions such as low temperature, mechanical stimulation, and oxygen deficiency (12, 13). As in other organisms, GABA is synthesized in plants primarily by decarboxylation of glutamate and degraded via succinic semialdehyde to succinate, a pathway that is also called the GABA shunt (12). Alternatively, succinic semialdehyde can be further catabolized to ␥-h...

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The metabolism of 4-aminobutyrate (GABA) in fungi

Cited by 86 publications

References 50 publications

A physiological role for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris

A physiological role for oxalic acid biosynthesis in the wood-rotting basidiomycete Fomitopsis palustris

Novel Route for Agmatine Catabolism in Aspergillus niger Involves 4-Guanidinobutyrase

AtGAT1, a High Affinity Transporter for γ-Aminobutyric Acid in Arabidopsis thaliana

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