Inter-domain cross-talk controls the NifA protein activity of Herbaspirillum seropedicae.
Herbaspirillum seropedicae is an endophytic diazotroph, which colonizes sugar cane, wheat, rice and maize. The activity of NifA, a transcriptional activator of nif genes in H. seropedicae, is controlled by ammonium ions through a mechanism involving its N-terminal domain. Here we show that this domain interacts specifically in vitro with the N-truncated NifA protein, as revealed by protection against proteolysis, and this interaction caused an inhibitory effect on both the ATPase and DNA-binding activities of the N-truncated NifA protein. We suggest that the N-terminal domain inhibits NifA-dependent transcriptional activation by an inter-domain cross-talk between the catalytic domain of the NifA protein and its regulatory N-terminal domain in response to fixed nitrogen.
Monteiro
R A
RA
Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, P.O. Box 19046, Curitiba, PR 81531-990, Brazil.
de Souza
E M
EM
Wassem
R
R
Yates
M G
MG
Pedrosa
F O
FO
Chubatsu
L S
LS
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020562:Betaproteobacteria / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020134:Catalytic Domain; D004269:DNA, Bacterial / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D017434:Protein Structure, Tertiary; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
D001426:Bacterial Proteins; D004269:DNA, Bacterial; C061338:NifA protein, Bacteria; D014157:Transcription Factors; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases