Drepper Thomas, Wiethaus Jessica, Giaourakis Daphne, Gross Silke, Schubert Britta, Vogt Markus, Wiencek Yvonne, McEwan Alastair G, Masepohl Bernd
Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Jülich, Germany.
FEMS Microbiol Lett. 2006 May;258(2):250-6. doi: 10.1111/j.1574-6968.2006.00228.x.
Rhodobacter capsulatus NtrB/NtrC two-component regulatory system controls expression of genes involved in nitrogen metabolism including urease and nitrogen fixation genes. The ntrY-ntrX genes, which are located immediately downstream of the nifR3-ntrB-ntrC operon, code for a two-component system of unknown function. Transcription of ntrY starts within the ntrC-ntrY intergenic region as shown by primer extension analysis, but maximal transcription requires, in addition, the promoter of the nifR3-ntrB-ntrC operon. While ntrB and ntrY single mutant strains were able to grow with either urea or N2 as sole nitrogen source, a ntrB/ntrY double mutant (like a ntrC-deficient strain) was no longer able to use urea or N2. These findings suggest that the histidine kinases NtrB and NtrY can substitute for each other as phosphodonors towards the response regulator NtrC.
荚膜红细菌NtrB/NtrC双组分调节系统控制参与氮代谢的基因的表达，包括脲酶和固氮基因。位于nifR3 - ntrB - ntrC操纵子下游紧邻位置的ntrY - ntrX基因编码一个功能未知的双组分系统。如引物延伸分析所示，ntrY的转录起始于ntrC - ntrY基因间区域，但最大转录量还需要nifR3 - ntrB - ntrC操纵子的启动子。虽然ntrB和ntrY单突变菌株能够以尿素或N2作为唯一氮源生长，但ntrB/ntrY双突变体（类似于ntrC缺陷菌株）不再能够利用尿素或N2。这些发现表明，组氨酸激酶NtrB和NtrY可以作为磷供体相互替代作用于应答调节因子NtrC。
