Open AccessRegulation of nitrogen fixation in Azospirillum brasilense
Author(s) -
Zhang Yaoping,
Burris Robert H,
Ludden Paul W,
Roberts Gary P
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb10428.x
Subject(s) - azospirillum brasilense , nitrogenase , rhodospirillum rubrum , nitrogen fixation , post translational regulation , diazotroph , biology , transcription (linguistics) , biochemistry , microbiology and biotechnology , bacteria , phosphorylation , enzyme , genetics , linguistics , philosophy
The regulation of nitrogen fixation in Azospirillum brasilense is very complicated, and it responds to exogenous fixed nitrogen or a change of oxygen concentration. This regulation occurs at both transcriptional and posttranslational levels. Unlike regulation seen in Klebsiella pneumoniae , transcription of nifA does not require NTRB/NTRC in A. brasilense and the expression of nifHDK is controlled by posttranslational regulation of NIFA activity. Addition of NH + 4 or a shift from microaerobic to anaerobic conditions also causes a rapid loss of nitrogenase activity in A. brasilense . This posttranslational regulation of nitrogenase activity involves the DRAT/DRAG regulatory system, which is similar to that of Rhodospirillum rubrum . Both DRAT and DRAG activities are regulated in vivo, but the mechanisms for their regulation are unknown.