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| | ==B. subtilis glutamine synthetase structures reveal large active site conformational changes and basis for isoenzyme specific regulation: form two of GS-1== | | ==B. subtilis glutamine synthetase structures reveal large active site conformational changes and basis for isoenzyme specific regulation: form two of GS-1== |
| - | <StructureSection load='4lno' size='340' side='right' caption='[[4lno]], [[Resolution|resolution]] 2.90Å' scene=''> | + | <StructureSection load='4lno' size='340' side='right'caption='[[4lno]], [[Resolution|resolution]] 2.90Å' scene=''> |
| | == Structural highlights == | | == Structural highlights == |
| - | <table><tr><td colspan='2'>[[4lno]] is a 6 chain structure with sequence from [http://en.wikipedia.org/wiki/"bacillus_globigii"_migula_1900 "bacillus globigii" migula 1900]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4LNO OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4LNO FirstGlance]. <br> | + | <table><tr><td colspan='2'>[[4lno]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Bacillus_subtilis Bacillus subtilis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4LNO OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4LNO FirstGlance]. <br> |
| - | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=GLN:GLUTAMINE'>GLN</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> | + | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GLN:GLUTAMINE'>GLN</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></td></tr> |
| - | <tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4lnf|4lnf]], [[4lni|4lni]], [[4lnk|4lnk]], [[4lnn|4lnn]]</td></tr>
| + | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=4lno FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4lno OCA], [https://pdbe.org/4lno PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4lno RCSB], [https://www.ebi.ac.uk/pdbsum/4lno PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4lno ProSAT]</span></td></tr> |
| - | <tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">glnA, BSU17460 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1423 "Bacillus globigii" Migula 1900])</td></tr>
| + | |
| - | <tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[http://en.wikipedia.org/wiki/Glutamate--ammonia_ligase Glutamate--ammonia ligase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=6.3.1.2 6.3.1.2] </span></td></tr>
| + | |
| - | <tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4lno FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4lno OCA], [http://pdbe.org/4lno PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=4lno RCSB], [http://www.ebi.ac.uk/pdbsum/4lno PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=4lno ProSAT]</span></td></tr> | + | |
| | </table> | | </table> |
| | + | == Function == |
| | + | [https://www.uniprot.org/uniprot/GLN1A_BACSU GLN1A_BACSU] Glutamine synthetase (GS) is an unusual multitasking protein that functions as an enzyme, a transcription coregulator, and a chaperone in ammonium assimilation and in the regulation of genes involved in nitrogen metabolism (PubMed:25691471). It catalyzes the ATP-dependent biosynthesis of glutamine from glutamate and ammonia (PubMed:24158439). Feedback-inhibited GlnA interacts with and regulates the activity of the transcriptional regulator TnrA (PubMed:11719184, PubMed:12139611). During nitrogen limitation, TnrA is in its DNA-binding active state and turns on the transcription of genes required for nitrogen assimilation (PubMed:11719184, PubMed:12139611, PubMed:25691471). Under conditions of nitrogen excess, feedback-inhibited GlnA forms a stable complex with TnrA, which inhibits its DNA-binding activity (PubMed:11719184, PubMed:12139611, PubMed:25691471). In contrast, feedback-inhibited GlnA acts as a chaperone to stabilize the DNA-binding activity of GlnR, which represses the transcription of nitrogen assimilation genes (PubMed:25691471).<ref>PMID:11719184</ref> <ref>PMID:12139611</ref> <ref>PMID:24158439</ref> <ref>PMID:25691471</ref> |
| | <div style="background-color:#fffaf0;"> | | <div style="background-color:#fffaf0;"> |
| | == Publication Abstract from PubMed == | | == Publication Abstract from PubMed == |
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| | </div> | | </div> |
| | <div class="pdbe-citations 4lno" style="background-color:#fffaf0;"></div> | | <div class="pdbe-citations 4lno" style="background-color:#fffaf0;"></div> |
| | + | |
| | + | ==See Also== |
| | + | *[[Glutamine synthetase 3D structures|Glutamine synthetase 3D structures]] |
| | == References == | | == References == |
| | <references/> | | <references/> |
| | __TOC__ | | __TOC__ |
| | </StructureSection> | | </StructureSection> |
| - | [[Category: Bacillus globigii migula 1900]] | + | [[Category: Bacillus subtilis]] |
| - | [[Category: Glutamate--ammonia ligase]] | + | [[Category: Large Structures]] |
| - | [[Category: Chinnam, N]] | + | [[Category: Chinnam N]] |
| - | [[Category: Fisher, S]] | + | [[Category: Fisher S]] |
| - | [[Category: Schumacher, M A]] | + | [[Category: Schumacher MA]] |
| - | [[Category: Tonthat, N]] | + | [[Category: Tonthat N]] |
| - | [[Category: Wray, L]] | + | [[Category: Wray L]] |
| - | [[Category: Alpha/beta]]
| + | |
| - | [[Category: Glnr]]
| + | |
| - | [[Category: Ligase]]
| + | |
| - | [[Category: Tnra]]
| + | |
| Structural highlights
Function
GLN1A_BACSU Glutamine synthetase (GS) is an unusual multitasking protein that functions as an enzyme, a transcription coregulator, and a chaperone in ammonium assimilation and in the regulation of genes involved in nitrogen metabolism (PubMed:25691471). It catalyzes the ATP-dependent biosynthesis of glutamine from glutamate and ammonia (PubMed:24158439). Feedback-inhibited GlnA interacts with and regulates the activity of the transcriptional regulator TnrA (PubMed:11719184, PubMed:12139611). During nitrogen limitation, TnrA is in its DNA-binding active state and turns on the transcription of genes required for nitrogen assimilation (PubMed:11719184, PubMed:12139611, PubMed:25691471). Under conditions of nitrogen excess, feedback-inhibited GlnA forms a stable complex with TnrA, which inhibits its DNA-binding activity (PubMed:11719184, PubMed:12139611, PubMed:25691471). In contrast, feedback-inhibited GlnA acts as a chaperone to stabilize the DNA-binding activity of GlnR, which represses the transcription of nitrogen assimilation genes (PubMed:25691471).[1] [2] [3] [4]
Publication Abstract from PubMed
Glutamine synthetase (GS), which catalyzes the production of glutamine (Q), plays essential roles in nitrogen metabolism. There are two main bacterial GS isoenzymes, GSI-alpha and GSI-beta. GSI-alpha enzymes, which have not been structurally characterized, are uniquely feedback inhibited by Q. To gain insight into GSI-alpha function, we performed biochemical and cellular studies and obtained structures for all GSI-alpha catalytic and regulatory states. GSI-alpha forms a massive 600 kDa dodecameric machine. Unlike other characterized GS, the B. subtilis enzyme undergoes dramatic intersubunit conformational alterations during formation of the transition state. Remarkably, these changes are required for active site construction. Feedback inhibition arises from a hydrogen-bond network between Q, the catalytic glutamate and GSI-alpha specific residue, Arg62, from an adjacent subunit. Notably, Arg62 must be ejected for proper active site reorganization. Consistent with these findings, a R62A mutation abrogates Q-feedback inhibition but does not affect catalysis. Thus, these data reveal a heretofore unseen restructuring of an enzyme active site that is coupled with an isoenzyme-specific regulatory mechanism. This GSI-alpha-specific regulatory network could be exploited for inhibitor design against Gram-positive pathogens.
Structures of the B. subtilis glutamine synthetase dodecamer reveal large intersubunit catalytic conformational changes linked to a unique feedback inhibition mechanism.,Murray DS, Chinnam N, Tonthat NK, Whitfill T, Wray LV, Fisher SH, Schumacher MA J Biol Chem. 2013 Oct 24. PMID:24158439[5]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Wray LV Jr, Zalieckas JM, Fisher SH. Bacillus subtilis glutamine synthetase controls gene expression through a protein-protein interaction with transcription factor TnrA. Cell. 2001 Nov 16;107(4):427-35. PMID:11719184
- ↑ Fisher SH, Brandenburg JL, Wray LV Jr. Mutations in Bacillus subtilis glutamine synthetase that block its interaction with transcription factor TnrA. Mol Microbiol. 2002 Aug;45(3):627-35. doi: 10.1046/j.1365-2958.2002.03054.x. PMID:12139611 doi:http://dx.doi.org/10.1046/j.1365-2958.2002.03054.x
- ↑ Murray DS, Chinnam N, Tonthat NK, Whitfill T, Wray LV, Fisher SH, Schumacher MA. Structures of the B. subtilis glutamine synthetase dodecamer reveal large intersubunit catalytic conformational changes linked to a unique feedback inhibition mechanism. J Biol Chem. 2013 Oct 24. PMID:24158439 doi:http://dx.doi.org/10.1074/jbc.M113.519496
- ↑ Schumacher MA, Chinnam NB, Cuthbert B, Tonthat NK, Whitfill T. Structures of regulatory machinery reveal novel molecular mechanisms controlling B. subtilis nitrogen homeostasis. Genes Dev. 2015 Feb 15;29(4):451-64. doi: 10.1101/gad.254714.114. PMID:25691471 doi:http://dx.doi.org/10.1101/gad.254714.114
- ↑ Murray DS, Chinnam N, Tonthat NK, Whitfill T, Wray LV, Fisher SH, Schumacher MA. Structures of the B. subtilis glutamine synthetase dodecamer reveal large intersubunit catalytic conformational changes linked to a unique feedback inhibition mechanism. J Biol Chem. 2013 Oct 24. PMID:24158439 doi:http://dx.doi.org/10.1074/jbc.M113.519496
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