scholarly journals High complexity of Glutamine synthetase regulation in Methanosarcina mazei : Small protein 26 interacts and enhances glutamine synthetase activity

FEBS Journal ◽  
2021 ◽  
Author(s):  
Miriam Gutt ◽  
Britta Jordan ◽  
Katrin Weidenbach ◽  
Mirja Gudzuhn ◽  
Claudia Kiessling ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
High Complexity ◽  
Small Protein ◽  
Methanosarcina Mazei

scholarly journals Small protein 26 interacts and enhances glutamine synthetase activity in Methanosarcina mazei

2020 ◽  
Author(s):  
Miriam Gutt ◽  
Britta Jordan ◽  
Katrin Weidenbach ◽  
Mirja Gudzuhn ◽  
Claudia Kiessling ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Affinity Chromatography ◽  
Nitrogen Limitation ◽  
Functional Characterization ◽  
Size Exclusion ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Small Protein ◽  
Methanosarcina Mazei ◽  
Small Proteins

ABSTRACTSmall ORFs (sORF) encoded small proteins have been overlooked for a long time due to challenges in prediction and distinguishing between coding and non-coding predicted sORFs and in their biochemical detection and characterization. We report on the first biochemical and functional characterization of a small protein (sP26) in the archaeal model organism Methanosarcina mazei, comprising 23 amino acids. The corresponding encoding leaderless mRNA (spRNA26) is highly conserved within numerous Methanosarcina strains on the amino acid as well as on nucleotide level strongly arguing for a cellular function of the small protein. spRNA26 is significantly enhanced under nitrogen limitation, but also under oxygen and salt stress conditions. His-tagged sP26 was heterologously expressed and purified by fractionated ammonium sulfate precipitation, affinity chromatography and size exclusion centrifugation. Using independent biochemical approaches (pull-down by affinity chromatography followed by MS analysis, revers pull-down, microscale thermophoresis and size exclusion chromatography) we observed that sP26 interacts and forms complexes with M. mazei glutamine synthetase (GlnA1) with high affinity (app. KD = 45 +/− 14 µM). Upon interaction with sP26, GlnA1 activity was significantly stimulated independently and in addition to the known activation by the metabolite 2-oxoglutarate. Besides strong interaction of sP26 with the PII-like protein GlnK1 was demonstrated (KD= 1.4 µM +/− 0.9 µM). On the basis of these findings, we hypothesize that in addition to 2-oxoglutarate, sP26 activates GlnA1 activity under nitrogen limitation most likely by stabilizing the dodecameric structure of GlnA1.

Respective effects of glucose and glutamine on the glutamine synthetase activity of human skin fibroblasts

1991 ◽  
Vol 102 (2) ◽  
Author(s):  
Th�ophile Soni ◽  
Claire Wolfrom ◽  
Samia Guerroui ◽  
Nicole Raynaud ◽  
Jos�phine Poggi ◽  
...  
Keyword(s):  
Glutamine Synthetase ◽  
Human Skin ◽  
Skin Fibroblasts ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Human Skin Fibroblasts

Control of nitrogen assimilation in Stichococcus bacillaris by growth conditions

1987 ◽  
Vol 65 (3) ◽  
pp. 432-437 ◽  
Author(s):  
Iftikhar Ahmad ◽  
Johan A. Hellebust
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Continuous Light ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Cell Carbon ◽  
Stichococcus Bacillaris ◽  
Mixotrophic Conditions

Stichococcus bacillaris Naeg. (Chlorophyceae) grown on a 12 h light: 12 h dark cycle divides synchronously under photoautotrophic conditions and essentially nonsynchronously under mixotrophic conditions. Photoassimilation of carbon under photoautotrophic conditions was followed by a decline in cell carbon content during the dark period, whereas under mixotrophic conditions cell carbon increased throughout the light–dark cycle. The rates of nitrogen assimilation by cultures grown on either nitrate or ammonium declined sharply during the dark, and these declines were most pronounced under photoautotrophic conditions. Photoautotrophic cells synthesized glutamine synthetase and NADPH – glutamate dehydrogenase (GDH) exclusively in the light, whereas in mixotrophic cells about 20% of the total synthesis of these enzymes during one light–dark cycle occurred in the dark. NADH–GDH was synthesized almost continuously over the entire light–dark cycle. In the dark, both under photoautotrophic and mixotrophic conditions, the alga contained more than 50% of glutamine synthetase in an inactive form, which was reactivated in vitro in the presence of mercaptoethanol and in vivo after returning the cultures to the light. The thermal stability of glutamine synthetase activity was less in light-harvested cells than in dark-harvested cells. The inactivation of glutamine synthetase did not occur in cultures growing either heterotrophically in continuous darkness or photoautotrophically in continuous light. This enzyme appears to be under thiol control only in cells grown under alternating light–dark conditions, irrespective of whether this light regime results in synchronous cell division or not.

scholarly journals Hydrocortisone requirement for the induction of glutamine synthetase in chick-embryo retinas

1968 ◽  
Vol 106 (2) ◽  
pp. 425-430 ◽  
Author(s):  
Liane Reif-Lehrer ◽  
Harold Amos
Keyword(s):  
Chick Embryo ◽  
Glutamine Synthetase ◽  
Messenger Rna ◽  
Active Component ◽  
Calf Serum ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity

Hydrocortisone has been found to induce glutamine synthetase activity in chick-embryo retinas in culture. Evidence is presented to show that the hydrocortisone is definitely required for transcription; its requirement for translation has not been ruled out. The possible identity of hydrocortisone with an active component of calf-serum diffusate reported earlier is discussed. The data also indicate that the glutamine synthetase messenger RNA is stable for at least several hours.

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