User:Adrian Aldrich/Prokaryotic Glutamine Synthetase Pfam Domains Outline
From Proteopedia
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| 1lgr, resolution 2.79Å () | |||||||||
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| Ligands: | , | ||||||||
| Activity: | Glutamate--ammonia ligase, with EC number 6.3.1.2 | ||||||||
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||
Prokaryotic Glutamine Synthetase Tertiary Structure: PFam domains
Prokaryotic Glutamine Synthetase is a dodecamer, comprised of 12 identical polypeptide chains, organized as a dimer of two disk like hexamers. Each protomer contains 2 Pfam domains, the Beta-grasp domain and the catalytic domain, preceded at the N terminus by short chains(3-13)of resides which link the all protomers together in the dodecamers core.
Beta Grasp domain
The is the N-terminal domain, extending from residues 13-94. This domain is responsible for binding ATP, Glutamate, and Ammonia. The domain folds into a bent beta-sheet flanked by two short alpha helices, forming a pocket for the ligands to bind. ATP binds first, activating the site for binding glutamate.
Catalytic domain
The is the C-terminal domain, extending from residues 101-382, and forms a melon rind shaped thin beta sheet coated on one side by several alpha helices.
Active site
The dodecamer contains 12 in total, each formed from the Beta-grasp domain of one protomer and the Catalytic domain of the neighboring protomer. The concave beta sheet of the Catalytic domain( in green ) faces the pocket of the neighboring Beta-grasp domain( in red ), creating a funnel shaped hollow in which binding and catalysis is performed.
