The Oxygen Sensor Protein, FixL, of Rhizobium meliloti
نویسندگان
چکیده
منابع مشابه
Assignment of the hyperfine-shifted 1H-NMR signals of the heme in the oxygen sensor FixL from Rhizobium meliloti.
BACKGROUND [corrected] The Rhizobial oxygen sensor FixL is a hemoprotein with kinase activity. On binding of strong-field ligands, a change of the ferrous or ferric heme iron from high to low spin reversibly inactivates the kinase. This spin-state change and other information on the heme pocket have been inferred from enzymatic assays, absorption spectra and mutagenesis studies. We set out to i...
متن کاملThe nifA gene of Rhizobium meliloti is oxygen regulated.
Experiments using plasmid-borne gene fusions and direct RNA measurements have revealed that expression from the nifA gene is induced in Rhizobium meliloti when the external oxygen concentration is reduced to microaerobic levels. Induction occurs in the absence of alfalfa and in the presence of fixed nitrogen and does not require ntrC. The production of functional nifA gene product (NifA) can be...
متن کاملThe FixL protein of Rhizobium meliloti can be separated into a heme-binding oxygen-sensing domain and a functional C-terminal kinase domain.
Transcription of nitrogen fixation (nif and fix) genes in Rhizobium meliloti is induced by a decrease in oxygen concentration. The products of two genes, fixL and fixJ, are responsible for sensing and transmitting the low-oxygen signal. The proteins encoded by fixL and fixJ (FixL and FixJ, respectively) are homologous to a family of bacterial proteins that transduce environmental signals throug...
متن کاملRhizobium meliloti nodulation genes: identification of nodDABC gene products, purification of nodA protein, and expression of nodA in Rhizobium meliloti.
A set of conserved, or common, bacterial nodulation (nod) loci is required for host plant infection by Rhizobium meliloti and other Rhizobium species. Four such genes, nodDABC, have been indicated in R. meliloti 1021 by genetic analysis and DNA sequencing. An essential step toward understanding the function of these genes is to characterize their protein products. We used in vitro and maxicell ...
متن کاملOxygen-regulated in vitro transcription of Rhizobium meliloti nifA and fixK genes.
Oxygen concentration regulates the expression of nitrogen fixation genes in the symbiotic bacterium Rhizobium meliloti. We demonstrate that two proteins, FixL and FixJ, that belong to the two-component family of regulatory proteins are necessary and sufficient for oxygen-regulated in vitro transcription of the two key regulatory genes, nifA and fixK. We show directly that FixJ is a transcriptio...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1995
ISSN: 0021-9258
DOI: 10.1074/jbc.270.10.5243