Regulation of synthesis of glutamine synthetase by adenylylated glutamine synthetase

Abstract

Three mutants of Klebsiella aerogenes were examined, whose genetic lesions (glnB, glnD, and glnE) are in loci unlinked to the structural gene for glutamine synthetase (glnA) and in which the control of both the level and state of adenylation of glutamine synthetase is altered. Each mutation alters a different component of the adenylylation system of glutamine synthetase [L glutamate:ammonia ligase (ADP forming), EC 6.3.1.2]. Inability of the cell to deadenylylate glutamine synthetase (glnB and glnD) greatly decreases its production, while inability to adenylylate glutamine synthetase (glnE) results in its constitutively high production. These results together with previous results indicate that adenylylated glutamine synthetase inhibits the transcription of glnA.