ADP-ribosylation of Rhizobium meliloti glutamine synthetase III in vivo.
The control of glutamine synthetase (GS), the first enzyme in the main pathway used by Rhizobium meliloti to assimilate ammonia, is central to cellular nitrogen metabolism. R. meliloti is unusual in having three distinct types of GS, including a unique GS, GSIII, that differs considerably from both GSI, which resembles other bacterial GS proteins and GSII, which resembles the GS found in eukaryotes. We show here that GSIII can be post-translationally modified in vivo by ADP-ribosylation at an arginine residue. 32PO4 attached to GSIII during bacterial growth as part of the modifying group could be removed by treatment with snake venom phosphodiesterase or by turkey erythrocyte ADP-ribosylarginine hydrolase. Treatment of modified GSIII with hydroxylamine at neutral pH releases a chromophore that has the retention time of ADP-ribose when analyzed by reversed-phase high performance liquid chromatography. ADP-ribosylation inhibits GSIII activity.
Liu
Y
Y
Department of Microbiology, Washington State University, Pullman 99164-6340.
Kahn
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ML
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism; D001345:Autoradiography; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli; D005974:Glutamate-Ammonia Ligase / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D006026:Glycoside Hydrolases; D006867:Hydrolases / Q000378:metabolism; D009699:N-Glycosyl Hydrolases; D010710:Phosphates / Q000378:metabolism; D010761:Phosphorus Radioisotopes; D011499:Protein Processing, Post-Translational; D016962:Sinorhizobium meliloti / Q000201:enzymology*
D010710:Phosphates; D010761:Phosphorus Radioisotopes; D000246:Adenosine Diphosphate Ribose; D000249:Adenosine Monophosphate; D006867:Hydrolases; D006026:Glycoside Hydrolases; D009699:N-Glycosyl Hydrolases; C046422:ADP-ribosylarginine hydrolase; D005974:Glutamate-Ammonia Ligase