Characterization of a novel β-alanine biosynthetic pathway consisting of promiscuous metabolic enzymes

Perchat, Nadia; Dubois, Christelle; Mor-Gautier, Rémi; Duquesne, Sophie; Lechaplais, Christophe; Roche, David; Fouteau, Stéphanie; Darii, Ekaterina; Perret, Alain

doi:10.1016/j.jbc.2022.102067

Cited by 4 publications

(7 citation statements)

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“…Also, a reduction of the level of β-alanine, a precursor of pantothenate, was observed in the metabolomic analysis of the dat mutant. Given the role of Dat in the synthesis of β-alanine described in other bacteria ( Perchat et al, 2022 ), we hypothesized that homoserine and DABA could be used as sources of pantothenate in Rlv UPM 791, and that Dat protein might be involved in this. To test this hypothesis, the growth of wild-type and dat -deficient strains in modified pantothenate-lacking UMS media containing each of the N sources cited above were compared.…”

Section: Resultsmentioning

confidence: 99%

“…The available data suggest that metabolism of Rlv UPM791 pea bacteroids is adapted to the presence of L-Hse as substrate, and it can be hypothesized that part of this substrate is converted into DABA via Dat. DABA has been recently shown as an intermediate for pantothenate synthesis through its involvement in the generation of β-alanine in Acinetobacter baylyi ( Perchat et al, 2022 ). Pantothenate is a precursor of CoA, a key compound for cells, particularly for those relying in tricarboxylic acid cycle.…”

Section: Discussionmentioning

confidence: 99%

“…The enzyme has been purified from different bacteria and biochemically characterized as a tetramer able to catalyze the reaction in both directions in vitro ( Ikai and Yamamoto, 1994 ; Ono et al, 1998 ; Hillier et al, 2020 ), in a manner mechanistically similar to other transaminases such as gamma-aminobutyrate transaminase ( Ono et al, 1999 ; Vandenende et al, 2004 ; Richter et al, 2019 ). DABA-AT enzyme is involved in several biological processes in endosymbiotic bacteria, including metabolism of ectoine, and synthesis of siderophores, polyamines, and pantothenate ( Ikai and Yamamoto, 1997 ; Lynch et al, 2001 ; Becerra-Rivera et al, 2020 ; Perchat et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

“…A recent report ( Perchat et al, 2022 ) has shown that DABA-AT enzyme participates in a pathway for the synthesis of β-alanine, a precursor of pantothenate, in bacterial mutants lacking aspartate decarboxylase (PanD). Although PanD is the only enzyme known to convert aspartate into β-alanine ( Dusch et al, 1999 ), most rhizobia, as well as many α- Proteobacteria , are known to lack this enzyme ( López-Sámano et al, 2020 ).…”

Section: Introductionmentioning

confidence: 99%

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A host-specific diaminobutyrate aminotransferase contributes to symbiotic performance, homoserine metabolism, and competitiveness in the Rhizobium leguminosarum/Pisum sativum system

Ballesteros-Gutiérrez,

Albareda,

Barbas

et al. 2023

Front. Microbiol.

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Rhizobium leguminosarum bv. viciae (Rlv) UPM791 effectively nodulates pea and lentil, but bacteroids contain a number of proteins differentially expressed depending on the host. One of these host-dependent proteins (C189) is similar to a diaminobutyrate-2-oxoglutarate aminotransferase (DABA-AT). DABA-AT activity was demonstrated with cell extracts and with purified protein, so C189 was renamed as Dat. The dat gene was strongly induced in the central, active area of pea nodules, but not in lentil. Mutants defective in dat were impaired in symbiotic performance with pea plants, exhibiting reduced shoot dry weight, smaller nodules, and a lower competitiveness for nodulation. In contrast, there were no significant differences between mutant and wild-type in symbiosis with lentil plants. A comparative metabolomic approach using cell-free extracts from bacteroids induced in pea and lentil showed significant differences among the strains in pea bacteroids whereas no significant differences were found in lentil. Targeted metabolomic analysis revealed that the dat mutation abolished the presence of 2,4-diaminobutyrate (DABA) in pea nodules, indicating that DABA-AT reaction is oriented toward the production of DABA from L-aspartate semialdehyde. This analysis also showed the presence of L-homoserine, a likely source of aspartate semialdehyde, in pea bacteroids but not in those induced in lentil. The dat mutant showed impaired growth when cells were grown with L-homoserine as nitrogen source. Inclusion of DABA or L-homoserine as N source suppressed pantothenate auxotropy in Rlv UPM791, suggesting DABA as source of the pantothenate precursor β-alanine. These data indicate that Rlv UPM791 Dat enzyme is part of an adaptation mechanism of this bacterium to a homoserine-rich environment such as pea nodule and rhizosphere.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A host-specific diaminobutyrate aminotransferase contributes to symbiotic performance, homoserine metabolism, and competitiveness in the Rhizobium leguminosarum/Pisum sativum system

Ballesteros-Gutiérrez,

Albareda,

Barbas

et al. 2023

Front. Microbiol.

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“…127,128 About 15% of cyanobacterial genomes appear to encode two enzymes (Dat: 2,4-diaminobutyrate aminotransferase and Ddc: 2,4-diaminobutyrate decarboxylase) that are the core of an alternate route to β-alanine production in Acinetobacter baylyi and evidently many other bacteria. 129 Neither Dat nor Ddc are found within Cyanothece or nitroplast genomes. Nonetheless, given the multiple routes to synthesize β-alanine, and perhaps the ability of the nitroplast to import it from the host (Section II.E.4), synthesis of pantothenate and Coenzyme A may not be a problem for the diatom nitroplasts.…”

Section: Iid1 General Overviewmentioning

confidence: 99%

Engineering of crop plants to facilitate bottom-up innovation: A possible role for broad host-range nitroplasts and neoplasts

Elhai¹

2023

Preprint

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The astonishing gains in agricultural output since the 1960's has come at an environmental cost. It has also failed to bring much benefit to sub-Saharan Africa, the region of the world that is predicted to have the greatest population increase in the coming decades and greatest agricultural need. The increase in productivity required to feed the billions that will soon be added to the world's population is more likely to succeed if creative direction lies in the hands of those most intimately acquainted with local agricultural concerns. Nitrogen has been a major limitation, particularly in sub-Saharan agriculture, and I look here at the prospect for extending biological nitrogen fixation to the crops and practices of local interest. A source of optimism in this historically intractable problem is the discovery in certain algae of natural organelles – nitroplasts – derived from unicellular cyanobacteria that fix N2. Transferring nitroplasts to land plants seems possible only if the organelles rely little on their hosts. A survey of the metabolic capabilities of three of them indicate different degrees of independence. The nitroplast from the diatom Rhopalodia gibberula may need nothing from its host except a source of carbon (the nature of which is explored). The nitroplast from another diatom, Epithema turgida, is somewhat less independent, while the nitroplast from Braarudosphaera bigelowii (called UCYN-A) requires a great deal from its host, including imported protein. The evolutionary route to acquire proteins may have been greatly simplified if nitroplasts share proteins with chloroplasts, a co-resident cyanobacteria-derived organelle. The genomes of the diatom nitroplasts suggest the presence of a few enzymes that are rare in cyanobacteria but seemingly well suited to the special needs of a nitrogen-fixing organelle. I describe how the host-range of nitroplasts might be explored and how a stripped down version, called a neoplast, might simplify strain modification to such a degree that the process becomes accessible to academic researchers with limited resources, even to individual farmers.

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A Praise of Imperfection

PERETÓ

2023

The First Steps of Life

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Characterization of a novel β-alanine biosynthetic pathway consisting of promiscuous metabolic enzymes

Cited by 4 publications

References 78 publications

A host-specific diaminobutyrate aminotransferase contributes to symbiotic performance, homoserine metabolism, and competitiveness in the Rhizobium leguminosarum/Pisum sativum system

A host-specific diaminobutyrate aminotransferase contributes to symbiotic performance, homoserine metabolism, and competitiveness in the Rhizobium leguminosarum/Pisum sativum system

Engineering of crop plants to facilitate bottom-up innovation: A possible role for broad host-range nitroplasts and neoplasts

A Praise of Imperfection

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