Interactions between PII proteins and the nitrogenase regulatory enzymes DraT and DraG in Azospirillum brasilense.
In Azospirillum brasilense ADP-ribosylation of dinitrogenase reductase (NifH) occurs in response to addition of ammonium to the extracellular medium and is mediated by dinitrogenase reductase ADP-ribosyltransferase (DraT) and reversed by dinitrogenase reductase glycohydrolase (DraG). The P(II) proteins GlnB and GlnZ have been implicated in regulation of DraT and DraG by an as yet unknown mechanism. Using pull-down experiments with His-tagged versions of DraT and DraG we have now shown that DraT binds to GlnB, but only to the deuridylylated form, and that DraG binds to both the uridylylated and deuridylylated forms of GlnZ. The demonstration of these specific protein complexes, together with our recent report of the ability of deuridylylated GlnZ to be sequestered to the cell membrane by the ammonia channel protein AmtB, offers new insights into the control of NifH ADP-ribosylation.
Huergo
Luciano F
LF
Department of Biochemistry and Molecular Biology, Universidade Federal do Paraná, CP 19046, 81531-990 Curitiba, PR, Brazil.
Chubatsu
Leda S
LS
Souza
Emanuel M
EM
Pedrosa
Fábio O
FO
Steffens
Maria B R
MB
Merrick
Mike
M
D015806:Azospirillum brasilense / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000201:enzymology* / Q000235:genetics; D004789:Enzyme Activation / Q000502:physiology; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D051922:PII Nitrogen Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding / Q000502:physiology; D011499:Protein Processing, Post-Translational / Q000502:physiology*
D001426:Bacterial Proteins; D027682:Cation Transport Proteins; C100965:GlnZ protein, Azospirillum brasilense; D046912:Multiprotein Complexes; D051922:PII Nitrogen Regulatory Proteins; C110078:draTG protein, Bacteria; D010088:Oxidoreductases; C029130:nitrogenase reductase