View source for 3la2


==Crystal structure of NtcA in complex with 2-oxoglutarate==
<StructureSection load='3la2' size='340' side='right'caption='[[3la2]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3la2]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Nostoc_sp._PCC_7120_=_FACHB-418 Nostoc sp. PCC 7120 = FACHB-418]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3LA2 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3LA2 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=AKG:2-OXOGLUTARIC+ACID'>AKG</scene></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=3la2 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3la2 OCA], [https://pdbe.org/3la2 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3la2 RCSB], [https://www.ebi.ac.uk/pdbsum/3la2 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3la2 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/NTCA_NOSS1 NTCA_NOSS1] Required for full expression of proteins subject to ammonium repression. Transcriptional activator of genes subject to nitrogen control.  Has affinity for the xisA upstream region. Binds to a 66 bp region containing three repeats of the consensus recognition sequence 5'-ACATT-3'.
== 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/la/3la2_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=3la2 ConSurf].
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== Publication Abstract from PubMed ==
2-oxogluatarate (2-OG), a metabolite of the highly conserved Krebs cycle, not only plays a critical role in metabolism, but also constitutes a signaling molecule in a variety of organisms ranging from bacteria to plants and animals. In cyanobacteria, the accumulation of 2-OG constitutes the signal of nitrogen starvation and NtcA, a global transcription factor, has been proposed as a putative receptor for 2-OG. Here we present three crystal structures of NtcA from the cyanobacterium Anabaena: the apoform, and two ligand-bound forms in complex with either 2-OG or its analogue 2,2-difluoropentanedioic acid. All structures assemble as homodimers, with each subunit composed of an N-terminal effector-binding domain and a C-terminal DNA-binding domain connected by a long helix (C-helix). The 2-OG binds to the effector-binding domain at a pocket similar to that used by cAMP in catabolite activator protein, but with a different pattern. Comparative structural analysis reveals a putative signal transmission route upon 2-OG binding. A tighter coiled-coil conformation of the two C-helices induced by 2-OG is crucial to maintain the proper distance between the two F-helices for DNA recognition. Whereas catabolite activator protein adopts a transition from off-to-on state upon cAMP binding, our structural analysis explains well why NtcA can bind to DNA even in its apoform, and how 2-OG just enhances the DNA-binding activity of NtcA. These findings provided the structural insights into the function of a global transcription factor regulated by 2-OG, a metabolite standing at a crossroad between carbon and nitrogen metabolisms.

Structural basis for the allosteric control of the global transcription factor NtcA by the nitrogen starvation signal 2-oxoglutarate.,Zhao MX, Jiang YL, He YX, Chen YF, Teng YB, Chen Y, Zhang CC, Zhou CZ Proc Natl Acad Sci U S A. 2010 Jul 13;107(28):12487-92. Epub 2010 Jun 28. PMID:20616047<ref>PMID:20616047</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Nostoc sp. PCC 7120 = FACHB-418]]
[[Category: Chen YF]]
[[Category: Chen YX]]
[[Category: He YX]]
[[Category: Jiang YL]]
[[Category: Teng YB]]
[[Category: Zhang CC]]
[[Category: Zhao MX]]
[[Category: Zhou CZ]]