View source for 2iyg


==Dark state structure of the BLUF domain of the rhodobacterial protein AppA==
<StructureSection load='2iyg' size='340' side='right'caption='[[2iyg]], [[Resolution|resolution]] 2.30&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2iyg]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Cereibacter_sphaeroides Cereibacter sphaeroides]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2IYG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2IYG 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]] 2.3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DTT:2,3-DIHYDROXY-1,4-DITHIOBUTANE'>DTT</scene>, <scene name='pdbligand=DTU:(2R,3S)-1,4-DIMERCAPTOBUTANE-2,3-DIOL'>DTU</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</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=2iyg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2iyg OCA], [https://pdbe.org/2iyg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2iyg RCSB], [https://www.ebi.ac.uk/pdbsum/2iyg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2iyg ProSAT]</span></td></tr>
</table>
== 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/iy/2iyg_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=2iyg ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Proteins containing a sensor of blue light using FAD (BLUF) domain control diverse cellular processes, such as gene expression, nucleotide metabolism and motility, by relaying blue light signals to distinct output units. Despite its crucial and widespread functions, the mechanism of BLUF signal transduction has remained elusive. We determined crystal structures of the dark-adapted state and of a photo-excited, red-shifted photocycle intermediate of the BLUF unit of AppA, a purple bacterial photoreceptor involved in the light-dependent regulation of photosynthesis gene expression. In contrast to a recently published crystal structure of the AppA BLUF domain determined in the presence of detergent molecules, our structural model of the dark state corresponds well to those reported for the BLUF domains of Tll0078 and BlrB. This establishes that a highly conserved methionine (Met106 in AppA) is next to the active site glutamine (Gln63 in AppA), which is of relevance for the latter's orientation in the dark state and for the mechanism of the photoreaction. The comparison of the dark-adapted and photointermediate state structures shows light-induced conformational alterations, which suggest a path for signal propagation. In particular, we observe a significant movement of the Met106 side-chain. Met106 thereby changes its mode of interaction with Gln63, which supports a light-dependent rotation of the latter. In view of other BLUF structures available, our data further suggest that the hydrogen bond between Asn45 and the backbone carbonyl of His105 breaks upon illumination. The ensuing extensive structural rearrangement of beta-strand 5 is predicted to involve a flip of Met106 out of the flavin-binding pocket and Trp104 moving in to fill the void. We propose that the blue light signal is transmitted towards the surface of the BLUF domain via His44, which serves as a reporter of active site changes.

Crystal structures of the AppA BLUF domain photoreceptor provide insights into blue light-mediated signal transduction.,Jung A, Reinstein J, Domratcheva T, Shoeman RL, Schlichting I J Mol Biol. 2006 Sep 29;362(4):717-32. Epub 2006 Jul 15. PMID:16949615<ref>PMID:16949615</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 2iyg" style="background-color:#fffaf0;"></div>

==See Also==
*[[AppA protein BLUF domain|AppA protein BLUF domain]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Cereibacter sphaeroides]]
[[Category: Large Structures]]
[[Category: Domratcheva T]]
[[Category: Jung A]]
[[Category: Reinstein J]]
[[Category: Schlichting I]]
[[Category: Shoeman R-L]]