2gnk: Difference between revisions

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-{{Seed}}
-[[Image:2gnk.png|left|200px]]
-<!--
+==GLNK, A SIGNAL PROTEIN FROM E. COLI==
-The line below this paragraph, containing "STRUCTURE_2gnk", creates the "Structure Box" on the page.
+<StructureSection load='2gnk' size='340' side='right'caption='[[2gnk]], [[Resolution|resolution]] 2.00&Aring;' scene=''>
-You may change the PDB parameter (which sets the PDB file loaded into the applet)
+== Structural highlights ==
-or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
+<table><tr><td colspan='2'>[[2gnk]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GNK OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2GNK FirstGlance]. <br>
-or leave the SCENE parameter empty for the default display.
+</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2&#8491;</td></tr>
--->
+<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ATP:ADENOSINE-5-TRIPHOSPHATE'>ATP</scene></td></tr>
-{{STRUCTURE_2gnk|  PDB=2gnk  |  SCENE=  }}
+<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2gnk FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2gnk OCA], [https://pdbe.org/2gnk PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2gnk RCSB], [https://www.ebi.ac.uk/pdbsum/2gnk PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2gnk ProSAT]</span></td></tr>
+</table>
+== Function ==
+[https://www.uniprot.org/uniprot/GLNK_ECOLI GLNK_ECOLI] P-II indirectly controls the transcription of the glutamine synthetase gene (glnA). P-II prevents NR-II-catalyzed conversion of NR-I to NR-I-phosphate, the transcriptional activator of GlnA. When P-II is uridylylated to P-II-UMP, these events are reversed. When the ratio of Gln to 2-ketoglutarate decreases, P-II is uridylylated to P-II-UMP, which causes the deadenylation of glutamine synthetase by GlnE, so activating the enzyme (By similarity).
+== Evolutionary Conservation ==
+[[Image:Consurf_key_small.gif|200px|right]]
+Check<jmol>
+  <jmolCheckbox>
+    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/gn/2gnk_consurf.spt"</scriptWhenChecked>
+    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
+    <text>to colour the structure by Evolutionary Conservation</text>
+  </jmolCheckbox>
+</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2gnk ConSurf].
+<div style="clear:both"></div>
+<div style="background-color:#fffaf0;">
+== Publication Abstract from PubMed ==
+GlnK is a recently discovered homologue of the PII signal protein, an indicator of the nitrogen status of bacteria. PII occupies a central position in the dual cascade that regulates the activity of glutamine synthetase and the transcription of its gene. The complete role of Escherichia coli GlnK is yet to be determined, but already it is known that GlnK behaves like PII and can substitute for PII under some circumstances thereby adding to the subtleties of nitrogen regulation. There are also indications that the roles of the two proteins differ; the expression of PII is constitutive while that of GlnK is linked to the level of nitrogen in the cell. The discovery of GlnK begs the question of why E. coli has both GlnK and PII. Clearly, the structural similarities and differences of GlnK and PII will lead to a better understanding of how PII-like proteins function in E. coli and other organisms. We have crystallised and solved the X-ray structure of GlnK at 2.0 A resolution. The asymmetric unit has two independent copies of the GlnK subunit and both pack around 3-fold axes to form trimers. The trimers have a barrel-like core with recognition loops (the T-loops) that protrude from the top of the molecule. The two GlnK molecules have similar core structures to PII but differ significantly at the C terminus and the loops. The T-loops of the two GlnK molecules also differ from each other; one is disordered while the conformation of the other is stabilised by lattice contacts. The conformation of the ordered T-loop of GlnK differs from that observed in the PII structure despite the fact that their sequences are very similar. The structures suggest that the T-loops do not have a rigid structure and that they may be flexible in solution. The presence of a turn of 310 helix in the middle of the T-loop suggests that secondary structure could form when it interacts with soluble receptor enzymes.Co-crystals of GlnK and ATP were used to determine the structure of the complex. In these crystals, GlnK occupies a position of 3-fold symmetry. ATP binds in a cleft on the side of the molecule. The cleft is suitably positioned for ATP to influence the flexible T-loops. It is found at the junction of two beta sheets and is formed by two peptides one of which contains a variant of the "Gly-loop" found in other mononucleotide binding proteins. This sequence, Thr-Gly-X-X-Gly-Asp-Gly-Lys-Ile-Phe, forms part of the B-loop and is conserved in a wide variety of organisms that include bacteria, algae and archeabacteria. This sequence is more highly conserved than the functional T-loop, suggesting that ATP has an important role in PII-like proteins.
-===GLNK, A SIGNAL PROTEIN FROM E. COLI===
+GlnK, a PII-homologue: structure reveals ATP binding site and indicates how the T-loops may be involved in molecular recognition.,Xu Y, Cheah E, Carr PD, van Heeswijk WC, Westerhoff HV, Vasudevan SG, Ollis DL J Mol Biol. 1998 Sep 11;282(1):149-65. PMID:9733647<ref>PMID:9733647</ref>
+From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
-<!--
+</div>
-The line below this paragraph, {{ABSTRACT_PUBMED_9733647}}, adds the Publication Abstract to the page
+<div class="pdbe-citations 2gnk" style="background-color:#fffaf0;"></div>
-(as it appears on PubMed at http://www.pubmed.gov), where 9733647 is the PubMed ID number.
+== References ==
--->
+<references/>
-{{ABSTRACT_PUBMED_9733647}}
+__TOC__
+</StructureSection>
-==About this Structure==
-GNK is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2GNK OCA].
-==Reference==
-GlnK, a PII-homologue: structure reveals ATP binding site and indicates how the T-loops may be involved in molecular recognition., Xu Y, Cheah E, Carr PD, van Heeswijk WC, Westerhoff HV, Vasudevan SG, Ollis DL, J Mol Biol. 1998 Sep 11;282(1):149-65. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/9733647 9733647]
 [[Category: Escherichia coli]]
-[[Category: Single protein]]
+[[Category: Large Structures]]
-[[Category: Carr, P D.]]
+[[Category: Carr PD]]
-[[Category: Cheah, E.]]
+[[Category: Cheah E]]
-[[Category: Heeswijk, W C.van.]]
+[[Category: Ollis DL]]
-[[Category: Ollis, D L.]]
+[[Category: Vasudevan SG]]
-[[Category: Vasudevan, S G.]]
+[[Category: Westerhoff HV]]
-[[Category: Westerhoff, H V.]]
+[[Category: Xu Y]]
-[[Category: Xu, Y.]]
+[[Category: Van Heeswijk WC]]
-[[Category: Signaling protein]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Mon Jul 28 05:20:37 2008''