User talk:Adrian Aldrich/Prokaryotic Glutamine Synthetase Pfam Domains
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[1] is a dodecamer, comprised of 12 identical polypeptide chains, organized as a dimer of two disk like hexamers. Each protomer contains 2 Pfam[2] 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[3], Glutamate[4], and Ammonia[5]. The domain folds into a bent beta-sheet[6] flanked by two short alpha helices[7], forming a pocket for the ligands to bind. ATP[8] 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[9] coated on one side by several alpha helices[10].
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.