Open AccessFnr Is Involved in Oxygen Control of Herbaspirillum seropedicae N-Truncated NifA Protein Activity in Escherichia coli
Author(s) -
Rose A. Monteiro,
Emanuel M. Souza,
M. G. Yates,
Fábio O. Pedrosa,
Leda S. Chubatsu
Publication year - 2003
Publication title -
applied and environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.552
H-Index - 324
eISSN - 1070-6291
pISSN - 0099-2240
DOI - 10.1128/aem.69.3.1527-1531.2003
Subject(s) - escherichia coli , diazotroph , microbiology and biotechnology , biology , activator (genetics) , gene , proteobacteria , biochemistry , bacteria , genetics , nitrogen fixation , 16s ribosomal rna
Herbaspirillum seropedicae is an endophytic diazotroph belonging to the beta-subclass of the class Proteobacteria, which colonizes many members of the Gramineae. The activity of the NifA protein, a transcriptional activator of nif genes in H. seropedicae, is controlled by ammonium ions through its N-terminal domain and by oxygen through mechanisms that are not well understood. Here we report that the NifA protein of H. seropedicae is inactive and more susceptible to degradation in an fnr Escherichia coli background. Both effects correlate with oxygen exposure and iron deprivation. Our results suggest that the oxygen sensitivity and iron requirement for H. seropedicae NifA activity involve the Fnr protein.