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Media type:
E-Article
Title:
Regulation of Glutamine Synthetase Activity by Adenylylation in the Gram-Positive Bacterium Streptomyces cattleya
Contributor:
Streicher, Stanley L.;
Tyler, Bonnie
imprint:
National Academy of Sciences of the United States of America, 1981
Published in:Proceedings of the National Academy of Sciences of the United States of America
Language:
English
ISSN:
0027-8424
Origination:
Footnote:
Description:
<p>The enzymatic activity of glutamine synthetase [GS; L-glutamate:ammonia ligase (ADP-forming), EC 6.3.1.2] from the Gram-positive bacterium Streptomyces cattleya is regulated by covalent modification. In whole cells containing high levels of GS the addition of ammonium chloride leads to a rapid decline in GS activity. Crude extracts prepared from such ammonia-shocked cells had very low levels of GS activity as measured by biosynthetic and γ -glutamyltransferase assays. Incubation of the crude extracts with snake venom phosphodiesterase restored GS activity. In cell extracts, GS was also inactivated by an ATP- and glutamine-dependent reaction. Radioactive labeling studies demonstrated the incorporation of an AMP moiety into GS protein upon modification. Our results suggest a covalent modification of GS in a Gram-positive bacterium. This modification appears to be adenylylation of the GS subunit similar to that found in the Gram-negative bacteria.</p>