GlnA

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• Description: trigger enzyme: glutamine synthetase and effector of TnrA and GlnR <br/><br/>

Gene name	glnA
Synonyms
Essential	no
Product	trigger enzyme: glutamine synthetase
Function	glutamine biosynthesis, control of TnrA and GlnR activity
Metabolic function and regulation of this protein in SubtiPathways: <br/>Ammonium/ glutamate
MW, pI	50 kDa, 4.874
Gene length, protein length	1332 bp, 444 aa
Immediate neighbours	glnR, ynxB
Get the DNA and protein sequences <br/> (Barbe et al., 2009)
Genetic context <br/> <div align="right"> <small>This image was kindly provided by SubtiList</small></div>

<br/><br/><br/><br/><br/><br/>

The gene

Basic information

• Locus tag: BSU17460

Phenotypes of a mutant

auxotrophic for glutamine

Database entries

• DBTBS entry: [1]

• SubtiList entry: [2]

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: ATP + L-glutamate + NH₃ = ADP + phosphate + L-glutamine (according to Swiss-Prot)

• Protein family: glutamine synthetase family (according to Swiss-Prot)

• Paralogous protein(s):

Extended information on the protein

• Kinetic information: K(M) for: Glu: 27 mM, ATP: 2.4 mM, ammonium: 0.18 mM; v(max): 3.7 µmol/min/mg

• Domains: glutamate binding flap (aa 300 ... 306: protects unstable intermediates from abberant hydrolysis)

• Modification: phosphorylated on ser/ thr/ tyr PubMed, in vitro phosphorylated by PrkC on Thr-26, Thr-147, Ser-207, and Thr-286 PubMed

• Cofactor(s): Mg(2+)

• Effectors of protein activity: feedback inhibition by glutamine, glutamine binds the entrance site for glutamate

• Interactions: TnrA-GlnA PubMed, GlnR-GlnA PubMed, (only the feedback-inhibited enzyme interacts with TnrA and GlnR)

• Localization: cytoplasm (according to Swiss-Prot)

Database entries

• Structure: 2GLS (enzyme from Salmonella typhimurium)

• UniProt: P12425

• KEGG entry: [3]

• E.C. number: 6.3.1.2

Additional information

GlnA is a homooligomer of 12 subunits

Expression and regulation

• Operon: glnR-glnA PubMed

• Sigma factor: SigA PubMed

• Regulation:
  • expressed in the absence of glutamine (GlnR) PubMed
  • repressed in the absence of good nitrogen sources (glutamine or ammonium) (TnrA) PubMed

• Regulatory mechanism:
  • GlnR-GlnA complex: transcription repression PubMed
  • TnrA: transcription repression PubMed

• Additional information:

Biological materials

• Mutant: GP247 (cat), available in Stülke lab

• Expression vector:
  • expression/ purification from E. coli, with N-terminal Strep-tag (in pGP172): pGP174, available in Stülke lab

• lacZ fusion: glnR-lacZ: pGP189 (in pAC7), available in Stülke lab

• GFP fusion:

• two-hybrid system:

• Antibody: available in Karl Forchhammer lab

Labs working on this gene/protein

Susan Fisher, Boston, USA homepage

References

Reviews

<pubmed> 10231480 18086213 </pubmed>

Original publications

<pubmed>19233925, 20389117,8799114,18195355, 11719184, 12139611, 2573733, 8636055, 19233925, 16493705, 16885465, 6141156 2906311 20656908 16055443 18331450 16547045 8093698 </pubmed>