AI Article Synopsis
- Glutamine synthetase (GS), produced by the glnA gene, converts L-glutamate and ammonium into L-glutamine and is crucial for nitrogen assimilation in A. brasilense.
- The A. brasilense strain HM053 exhibits low GS activity and releases ammonium when fixing nitrogen, indicating a potential issue in its nitrogen assimilation process.
- Researchers cloned, sequenced, and overexpressed the glnA genes from both the wild type and HM053 strains in E. coli, revealing that a P347L mutation in HM053's GS leads to reduced enzyme activity and makes it unresponsive to regulation by the enzyme GlnE.
Article Abstract
Glutamine synthetase (GS), encoded by glnA, catalyzes the conversion of L-glutamate and ammonium to L-glutamine. This ATP hydrolysis driven process is the main nitrogen assimilation pathway in the nitrogen-fixing bacterium Azospirillum brasilense. The A. brasilense strain HM053 has poor GS activity and leaks ammonium into the medium under nitrogen fixing conditions. In this work, the glnA genes of the wild type and HM053 strains were cloned into pET28a, sequenced and overexpressed in E. coli. The GS enzyme was purified by affinity chromatography and characterized. The GS of HM053 strain carries a P347L substitution, which results in low enzyme activity and rendered the enzyme insensitive to adenylylation by the adenilyltransferase GlnE.
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| http://dx.doi.org/10.1590/1519-6984.235927 | DOI Listing |
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