On the flexibility of the cellular amination network in E. coli
- Max Planck Institute of Molecular Plant Physiology, Germany
- Max Planck Institute for Terrestrial Microbiology, Germany
Abstract
Ammonium (NH4+) is essential to generate the nitrogenous building blocks of life. It gets assimilated via the canonical biosynthetic routes to glutamate and is further distributed throughout metabolism via a network of transaminases. To study the flexibility of this network, we constructed an Escherichia coli glutamate auxotrophic strain. This strain allowed us to systematically study which amino acids serve as amine sources and found that several amino acids complement the auxotrophy, either by producing glutamate via transamination reactions or by their conversion to glutamate. In this network, we identified aspartate transaminase AspC as a major connector between many amino acids and glutamate. Additionally, we extended the transaminase network by the amino acids β-alanine, alanine, glycine, and serine as new amine sources and identified d-amino acid dehydrogenase (DadA) as an intracellular amino acid sink removing substrates from transaminase reactions. Finally, ammonium assimilation routes producing aspartate or leucine were introduced. Our study reveals the high flexibility of the cellular amination network, both in terms of transaminase promiscuity and adaptability to new connections and ammonium entry points.
Data availability
sequencing data has been deposited at Dryad
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Data from: On the flexibility of the cellular amination network in E. coliDryad Digital Repository, doi:10.5061/dryad.mcvdnck2s.
Article and author information
Author details
Helena Schulz-Mirbach
Funding
Bundesministerium für Bildung und Forschung (031B0825B)
- Steffen N Lindner
Deutsche Forschungsgemeinschaft (SFB987)
- Tobias J Erb
Max Planck Institute of Molecular Plant Physiology (open access funding)
- Helena Schulz-Mirbach
- Alexandra Müller
- Tong Wu
- Selçuk Aslan
- Arren Bar-Even
- Steffen N Lindner
Max Planck Institute for Terrestrial Microbiology (open access funding)
- Pascal Pfister
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, Schulz-Mirbach et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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On the flexibility of the cellular amination network in E. coli
eLife 11:e77492.
https://doi.org/10.7554/eLife.77492
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