Open AccessADP-ribosylation of glutamine synthetase in the cyanobacterium Synechocystis sp. strain PCC 6803
Author(s) -
N.J. Silman,
N. G. Carr,
Nicholas H. Mann
Publication year - 1995
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.177.12.3527-3533.1995
Subject(s) - glutamine synthetase , biology , biochemistry , nad+ kinase , synechocystis , transferase , enzyme , glutamine , adp ribosylation , strain (injury) , glutamate synthase , ammonium , microbiology and biotechnology , amino acid , chemistry , gene , organic chemistry , anatomy , mutant
Glutamine synthetase (GS) inactivation was observed in crude cell extracts and in the high-speed supernatant fraction from the cyanobacterium Synechocystis sp. strain PCC 6803 following the addition of ammonium ions, glutamine, or glutamate. Dialysis of the high-speed supernatant resulted in loss of inactivation activity, but this could be restored by the addition of NADH, NADPH, or NADP+ and, to a lesser extent, NAD+, suggesting that inactivation of GS involved ADP-ribosylation. This form of modification was confirmed both by labelling experiments using [32P]NAD+ and by chemical analysis of the hydrolyzed enzyme. Three different forms of GS, exhibiting no activity, biosynthetic activity only, or transferase activity only, could be resolved by chromatography, and the differences in activity were correlated with the extent of the modification. Both biosynthetic and transferase activities were restored to the completely inactive form of GS by treatment with phosphodiesterase.