NifA is the master regulator of both nitrogenase systems in Rhodobacter capsulatus
| Autor: | Julia E. Bandow, Bernd Masepohl, Sina Schäkermann, Lisa Demtröder, Yvonne Pfänder |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Proteomics
Proteome Nitrogen lcsh:QR1-502 Microbiology Cofactor Gene Expression Regulation Enzymologic Rhodobacter capsulatus lcsh:Microbiology chemistry.chemical_compound Biosynthesis Bacterial Proteins Transcription (biology) Sigma factor Genes Reporter Nitrogen Fixation Mo‐nitrogenase Rhodobacter Gene Binding Sites NifA regulon biology Chemistry Fe‐nitrogenase AnfA regulon Nitrogenase Original Articles Gene Expression Regulation Bacterial biochemical phenomena metabolism and nutrition biology.organism_classification Biochemistry Genes Bacterial Multigene Family biology.protein rpoN bacteria Original Article Protein Binding Transcription Factors |
| Zdroj: | MicrobiologyOpen, Vol 8, Iss 12, Pp n/a-n/a (2019) MicrobiologyOpen |
| ISSN: | 2045-8827 |
| Popis: | Rhodobacter capsulatus fixes atmospheric nitrogen (N2) by a molybdenum (Mo)‐nitrogenase and a Mo‐free iron (Fe)‐nitrogenase, whose production is induced or repressed by Mo, respectively. At low nanomolar Mo concentrations, both isoenzymes are synthesized and contribute to nitrogen fixation. Here we examined the regulatory interplay of the central transcriptional activators NifA and AnfA by proteome profiling. As expected from earlier studies, synthesis of the structural proteins of Mo‐nitrogenase (NifHDK) and Fe‐nitrogenase (AnfHDGK) required NifA and AnfA, respectively, both of which depend on the alternative sigma factor RpoN to activate expression of their target genes. Unexpectedly, NifA was found to be essential for the synthesis of Fe‐nitrogenase, electron supply to both nitrogenases, biosynthesis of their cofactors, and production of RpoN. Apparently, RpoN is the only NifA‐dependent factor required for target gene activation by AnfA, since plasmid‐borne rpoN restored anfH transcription in a NifA‐deficient strain. However, plasmid‐borne rpoN did not restore Fe‐nitrogenase activity in this strain. Taken together, NifA requirement for synthesis and activity of both nitrogenases suggests that Fe‐nitrogenase functions as a complementary nitrogenase rather than an alternative isoenzyme in R. capsulatus. In Rhodobacter capsulatus, biological nitrogen fixation is catalyzed by the molybdenum nitrogenase and a Mo‐free iron‐only nitrogenase. Here, we show that NifA controls synthesis of both nitrogenases by controlling synthesis of the sigma factor RpoN. |
| Databáze: | OpenAIRE |
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