Glutamine synthetase

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Glutamine synthetase (GS) is an essential enzyme in the cellular nitrogen metabolism and has been found to play a role in both ammonia assimilation and glutamine byosynthesis.<ref>PMID:8096645 </ref> GS is the only enzyme capable of glutamine synthesis, which is an essential precursor for purine and pyrimidine synthesis, a modulator of protein turnover or an intermediate for gluconeogenesis and acid-base balancce. <ref>Youji He,Theodorus B.M. Hakvoort, S.Eleonor Kohler, Jacqueline L.M. Vermeulen, D. Rudi de Waart, hiel de Theije, GabrieA.M. ten Have, Hans M.H. van Eijk, Cindy Kunne, Wilelmina T. Labruyere, Sander M. Houten, Mika Sokolovic, Jan M. Tuijter, Nicolaas E.P. Deutz and Wouter H. Lamers, The American Society for Biochemistry and Molecular Biology, January 11, 2010 </ref>
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Glutamine synthetase (GS) is an essential enzyme in the cellular nitrogen metabolism and has been found to play a role in both ammonia assimilation and glutamine byosynthesis.<ref>PMID:8096645 </ref> GS is the only enzyme capable of glutamine synthesis, which is an essential precursor for purine and pyrimidine synthesis, a modulator of protein turnover or an intermediate for gluconeogenesis and acid-base balancce. <ref>Youji He,Theodorus B.M. Hakvoort, S.Eleonor Kohler, Jacqueline L.M. Vermeulen, D. Rudi de Waart, hiel de Theije, GabrieA.M. ten Have, Hans M.H. van Eijk, Cindy Kunne, Wilelmina T. Labruyere, Sander M. Houten, Mika Sokolovic, Jan M. Tuijter, Nicolaas E.P. Deutz and Wouter H. Lamers. Glutamine Synthetase in muscle is required for glutamine produtciont druing fasting and extrahepatic ammonia detoxification. The American Society for Biochemistry and Molecular Biology, January 11, 2010 </ref>
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Revision as of 07:12, 25 March 2010

Rhiannon Khela


Please do NOT make changes to this Sandbox until after April 23, 2010. Sandboxes 151-200 are reserved until then for use by the Chemistry 307 class at UNBC taught by Prof. Andrea Gorrell.

Contents

Structure

An unrefined structure of glutamine synthetase is made of two layers, each containing 6 subunits, for a total of 12 subunits. [1] Each subunit contains an active site which is defined by a cylindrical shape formed by six antiparalel β starnds contributed by one subunit and two more strands by the neighbouring subunit.[2] In each cylindrical active site there are two Mn2+ ions. Both are attached to three protein chains and two water molecules, one of the water molecules are shared by both Mn2+. The protein ligands attached to Mn 2+ 469 are: Glu-131, GLu-212 and Glu-220. On the other hand, the protein ligands attached to Mn2+ are: Glu-129, His-269 and Glu-357.


PDB ID 2gls

Drag the structure with the mouse to rotate
2gls, resolution 3.50Å ()
Ligands:
Activity: Glutamate--ammonia ligase, with EC number 6.3.1.2
Resources: FirstGlance, OCA, PDBsum, RCSB
Coordinates: save as pdb, mmCIF, xml



Classes

Glutamine synthetase has been described as having three destinctive types:[3] Image:2gls120.png

  • Class I (GSI): Genes for this class have only been found in bacteria (eubacteria) and archaea (arhaebacteria)
  • Class II (GSII): Genes for this class have only been found in eukaryotes anda few soil-dwelling bacteria.
  • Class III (GSIII): Genes from this class have only been found in a few bacterial species.It is a hexamer of identical chains. It is much larger (about 700 amino acids) than the GSI (450 to 470 amino acids) or GSII (350 to 420 amino acids) enzymes.


Function

Glutamine synthetase (GS) is an essential enzyme in the cellular nitrogen metabolism and has been found to play a role in both ammonia assimilation and glutamine byosynthesis.[4] GS is the only enzyme capable of glutamine synthesis, which is an essential precursor for purine and pyrimidine synthesis, a modulator of protein turnover or an intermediate for gluconeogenesis and acid-base balancce. [5] Image:Glutamine-synthesis.jpg

References

  1. ↑ Yamashita MM, Almassy RJ, Janson CA, Cascio D, Eisenberg D. Refined atomic model of glutamine synthetase at 3.5 A resolution. J Biol Chem. 1989 Oct 25;264(30):17681-90. PMID:2572586
  2. ↑ Yamashita MM, Almassy RJ, Janson CA, Cascio D, Eisenberg D. Refined atomic model of glutamine synthetase at 3.5 A resolution. J Biol Chem. 1989 Oct 25;264(30):17681-90. PMID:2572586
  3. ↑ Brown JR, Masuchi Y, Robb FT, Doolittle WF. Evolutionary relationships of bacterial and archaeal glutamine synthetase genes. J Mol Evol. 1994 Jun;38(6):566-76. PMID:7916055
  4. ↑ Kumada Y, Benson DR, Hillemann D, Hosted TJ, Rochefort DA, Thompson CJ, Wohlleben W, Tateno Y. Evolution of the glutamine synthetase gene, one of the oldest existing and functioning genes. Proc Natl Acad Sci U S A. 1993 Apr 1;90(7):3009-13. PMID:8096645
  5. ↑ Youji He,Theodorus B.M. Hakvoort, S.Eleonor Kohler, Jacqueline L.M. Vermeulen, D. Rudi de Waart, hiel de Theije, GabrieA.M. ten Have, Hans M.H. van Eijk, Cindy Kunne, Wilelmina T. Labruyere, Sander M. Houten, Mika Sokolovic, Jan M. Tuijter, Nicolaas E.P. Deutz and Wouter H. Lamers. Glutamine Synthetase in muscle is required for glutamine produtciont druing fasting and extrahepatic ammonia detoxification. The American Society for Biochemistry and Molecular Biology, January 11, 2010
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