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A novel mechanism of glutamine synthetase inactivation by ammonium in the cyanobacterium Synechocystis sp . PCC 6803. Involvement of an inactivating protein
Author(s) -
Reyes J.C.,
Florencio F.J.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00544-j
Subject(s) - glutamine synthetase , synechocystis , biochemistry , glutamine , enzyme , protein subunit , western blot , ammonium , biology , chemistry , microbiology and biotechnology , amino acid , gene , organic chemistry , mutant
The glutamine synthetase of the cyanobacterium Synechocystis sp . PCC 6803 can be inactivated in vivo by ammonium addition by a new mechanism that involves the binding to the enzyme of an inactivating factor. This binding provokes a different mobility of the inactive enzyme with respect to the active form in non‐denaturing PAGE, but not in SDS‐PAGE. This modification of glutamine synthetase is for the first time visualized by Western blot analysis of the active and inactive forms. Cross‐linking experiments using 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) demonstrate the existence of two main complexes of 56 kDa and 67 kDa between the inactivating factor and the glutamine synthetase subunit (53 kDa) in the inactive but not in the active form of glutamine synthetase.