Sandbox2qc8
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Within each subunit there are 46 β-turns. These β-turns join secondary structures such as β-sheets and alpha helices when they need to abruptly change directions and usually occur at the protein surface.<ref name="wiley"/><br> | Within each subunit there are 46 β-turns. These β-turns join secondary structures such as β-sheets and alpha helices when they need to abruptly change directions and usually occur at the protein surface.<ref name="wiley"/><br> | ||
| - | In addition, β-loops protrude into the <scene name='Sandbox2qc8/12_loops_of_center/1'>aqueous central channel</scene>, allowing for additional quaternary stability. <br> | + | In addition, β-loops protrude into the <scene name='Sandbox2qc8/12_loops_of_center/1'>aqueous central channel</scene>, allowing for additional quaternary stability.<ref>Yamashita, M. M., et.al., Refined Atolnic Model of Glutamine Synthetase at 3.5 A Resolution, J Biol Chem 1989 264: 17681-17690.</ref> <br> |
Revision as of 03:48, 20 December 2008
Glutamine Synthetase: Secondary structures
Glutamine synthetase is composed of 12 . Each subunit is composed of 15 and . Each subunit binds 2 Mn for a total of per Glutamine Synthetase.
The β-strands are arranged into 5 . In addition, there are 5 and 5 . [1] β-bulges are distortions in β-sheets resulting from the addition of an extra residue due to mutation. Their presence allows the proteins to conserve their structure by maintaining the hydrogen bond pattern.[2] At the level of the backbone structure, these β-bulges can cause a simple aneurysm of the β-sheet. Furthermore, each β-bulge can cause a β-sheet to fold over and cross itself.
Within each subunit there are 46 β-turns. These β-turns join secondary structures such as β-sheets and alpha helices when they need to abruptly change directions and usually occur at the protein surface.[2]
In addition, β-loops protrude into the , allowing for additional quaternary stability.[3]
Each subunit has an exposed NH2 terminus and buried COOH terminus as part of a , colored in red. The helical thong is used as an anchor inside another subunit. [4]
The active site within the secondary structure can be called a "bifunnel," providing access to ATP and glutamate at opposing ends.[5]
The only ligand present is a pair of Mn ions (Manganese) that indicates the active site of each subunit of the dodecamer.
Glutamine synthetase contains the .
References
- ↑ European Bioinformatics Institute, Ligase(amide synthetase), http://www.ebi.ac.uk/thornton-srv/databases/cgi-bin/pdbsum/GetPage.pl?pdbcode=2gls, Accessed December 18, 2008.
- ↑ 2.0 2.1 Donald Voet, Judith G. Voet, Charlotte W. Pratt. Fundamentals of Biochemistry life at the molecular level. New Jersey: Wiley,2006.
- ↑ Yamashita, M. M., et.al., Refined Atolnic Model of Glutamine Synthetase at 3.5 A Resolution, J Biol Chem 1989 264: 17681-17690.
- ↑ Yamashita, M., et al.,Refined Atomic Model of Glutamine Synthetase at 3.5A Resolution, The Journal of Biological Chemistry, 1989, 17681-17690.
- ↑ Eisenberg, D., et al., Structure-function relationships of glutamine synthetases, Biochimica et Biophysica Acta 1477 (2000), 122-145.
