AUTHOR=Tsoy Olga V. , Ravcheev Dmitry A. , Čuklina Jelena , Gelfand Mikhail S. 

TITLE=Nitrogen Fixation and Molecular Oxygen: Comparative Genomic Reconstruction of Transcription Regulation in Alphaproteobacteria

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.01343

DOI=10.3389/fmicb.2016.01343

ISSN=1664-302X

ABSTRACT=<p>Biological nitrogen fixation plays a crucial role in the nitrogen cycle. An ability to fix atmospheric nitrogen, reducing it to ammonium, was described for multiple species of <italic>Bacteria</italic> and <italic>Archaea</italic>. The transcriptional regulatory network for nitrogen fixation was extensively studied in several representatives of the class <italic>Alphaproteobacteria</italic>. This regulatory network includes the activator of nitrogen fixation NifA, working in tandem with the alternative sigma-factor RpoN as well as oxygen-responsive regulatory systems, one-component regulators FnrN/FixK and two-component system FixLJ. Here we used a comparative genomics approach for <italic>in silico</italic> study of the transcriptional regulatory network in 50 genomes of <italic>Alphaproteobacteria</italic>. We extended the known regulons and proposed the scenario for the evolution of the nitrogen fixation transcriptional network. The reconstructed network substantially expands the existing knowledge of transcriptional regulation in nitrogen-fixing microorganisms and can be used for genetic experiments, metabolic reconstruction, and evolutionary analysis.</p>