View source for 6i20


==Flavin Analogue Sheds Light on Light-Oxygen-Voltage Domain Mechanism==
<StructureSection load='6i20' size='340' side='right'caption='[[6i20]], [[Resolution|resolution]] 1.37&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6i20]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6I20 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6I20 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene>, <scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=FMN:FLAVIN+MONONUCLEOTIDE'>FMN</scene>, <scene name='pdbligand=MES:2-(N-MORPHOLINO)-ETHANESULFONIC+ACID'>MES</scene></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=6i20 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6i20 OCA], [http://pdbe.org/6i20 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6i20 RCSB], [http://www.ebi.ac.uk/pdbsum/6i20 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6i20 ProSAT]</span></td></tr>
</table>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Light-oxygen-voltage (LOV) domains are increasingly used to engineer photoresponsive biological systems. While the photochemical cycle is well documented, the allosteric mechanism by which formation of a cysteinyl-flavin adduct leads to activation is unclear. Via replacement of flavin mononucleotide (FMN) with 5-deazaflavin mononucleotide (5dFMN) in the Aureochrome1a (Au1a) transcription factor from Ochromonas danica, a thermally stable cysteinyl-5dFMN adduct was generated. High-resolution crystal structures (&lt;2 A) under different illumination conditions with either FMN or 5dFMN chromophores reveal three conformations of the highly conserved glutamine 293. An allosteric hydrogen bond network linking the chromophore via Gln293 to the auxiliary A'alpha helix is observed. With FMN, a "flip" of the Gln293 side chain occurs between dark and lit states. 5dFMN cannot hydrogen bond through the C5 position and proved to be unable to support Au1a domain dimerization. Under blue light, the Gln293 side chain instead "swings" away in a conformation distal to the chromophore and not previously observed in existing LOV domain structures. Together, the multiple side chain conformations of Gln293 and functional analysis of 5dFMN provide new insight into the structural requirements for LOV domain activation.

A Noncanonical Chromophore Reveals Structural Rearrangements of the Light-Oxygen-Voltage Domain upon Photoactivation.,Kalvaitis ME, Johnson LA, Mart RJ, Rizkallah P, Allemann RK Biochemistry. 2019 May 17. doi: 10.1021/acs.biochem.9b00255. PMID:31082213<ref>PMID:31082213</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6i20" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Allemann, R K]]
[[Category: Johnson, L A]]
[[Category: Kalvaitis, M E]]
[[Category: Mart, R J]]
[[Category: Rizkallah, P J]]
[[Category: Dark grown]]
[[Category: Fluorescence]]
[[Category: Fmn]]
[[Category: Light sensing]]
[[Category: Lov domain]]
[[Category: Ochronomas danica]]
[[Category: Transcription]]
[[Category: Transcription factor pas domain]]