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==Crystal Structure of the blue-light absorbing form of the Thermosynechococcus elongatus PixJ GAF-domain== | |||
<StructureSection load='4glq' size='340' side='right' caption='[[4glq]], [[Resolution|resolution]] 1.77Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[4glq]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Theeb Theeb] and [http://en.wikipedia.org/wiki/Thermosynechococcus_elongatus_bp-1 Thermosynechococcus elongatus bp-1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4GLQ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=4GLQ FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=VRB:PHYCOVIOLOBILIN,+BLUE+LIGHT-ABSORBING+FORM'>VRB</scene></td></tr> | |||
<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[4fof|4fof]]</td></tr> | |||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">tll0569 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=197221 Thermosynechococcus elongatus BP-1]), HO1 and PcyA ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=197221 THEEB])</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=4glq FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4glq OCA], [http://www.rcsb.org/pdb/explore.do?structureId=4glq RCSB], [http://www.ebi.ac.uk/pdbsum/4glq PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The phytochrome superfamily encompasses a diverse collection of photochromic photoreceptors in plants and microorganisms that employ a covalently linked bilin cradled in a cGMP-phosphodiesterase/adenylyl-cyclase/FhlA (GAF) domain to detect light. Whereas most interconvert between red- and far-red-light-absorbing states, cyanobacteria also express variants called cyanobacteriochromes (CBCRs) that modify bilin absorption to collectively perceive the entire visible spectrum. Here, we present two X-ray crystallographic structures of the GAF domain from the blue/green photochromic CBCR PixJ from Thermosynechococcus elongatus. These structures confirm the hypothesis that CBCRs variably manipulate the chromophore pi-conjugation system through isomerization and a second thioether linkage, in this case involving the bilin C10 carbon and Cys494 within a DXCF sequence characteristic of blue/green CBCRs. Biochemical studies support a mechanism for photoconversion whereby the second linkage ruptures on route to the green-light-absorbing state. Collectively, the TePixJ(GAF) models illustrate the remarkable structural and photochemical versatility among phytochromes and CBCRs in driving light perception. | |||
A Photo-Labile Thioether Linkage to Phycoviolobilin Provides the Foundation for the Blue/Green Photocycles in DXCF-Cyanobacteriochromes.,Burgie ES, Walker JM, Phillips GN Jr, Vierstra RD Structure. 2013 Jan 8;21(1):88-97. doi: 10.1016/j.str.2012.11.001. Epub 2012 Dec , 6. PMID:23219880<ref>PMID:23219880</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | |||
*[[Chemotaxis protein|Chemotaxis protein]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Theeb]] | |||
[[Category: Thermosynechococcus elongatus bp-1]] | [[Category: Thermosynechococcus elongatus bp-1]] | ||
[[Category: Burgie, E S | [[Category: Burgie, E S]] | ||
[[Category: Phillips,, G N | [[Category: Phillips,, G N]] | ||
[[Category: Vierstra, R D | [[Category: Vierstra, R D]] | ||
[[Category: Walker, J M | [[Category: Walker, J M]] | ||
[[Category: Bili-protein]] | [[Category: Bili-protein]] | ||
[[Category: Bilin]] | [[Category: Bilin]] | ||
Revision as of 12:10, 15 February 2015
Crystal Structure of the blue-light absorbing form of the Thermosynechococcus elongatus PixJ GAF-domainCrystal Structure of the blue-light absorbing form of the Thermosynechococcus elongatus PixJ GAF-domain
Structural highlights
Publication Abstract from PubMedThe phytochrome superfamily encompasses a diverse collection of photochromic photoreceptors in plants and microorganisms that employ a covalently linked bilin cradled in a cGMP-phosphodiesterase/adenylyl-cyclase/FhlA (GAF) domain to detect light. Whereas most interconvert between red- and far-red-light-absorbing states, cyanobacteria also express variants called cyanobacteriochromes (CBCRs) that modify bilin absorption to collectively perceive the entire visible spectrum. Here, we present two X-ray crystallographic structures of the GAF domain from the blue/green photochromic CBCR PixJ from Thermosynechococcus elongatus. These structures confirm the hypothesis that CBCRs variably manipulate the chromophore pi-conjugation system through isomerization and a second thioether linkage, in this case involving the bilin C10 carbon and Cys494 within a DXCF sequence characteristic of blue/green CBCRs. Biochemical studies support a mechanism for photoconversion whereby the second linkage ruptures on route to the green-light-absorbing state. Collectively, the TePixJ(GAF) models illustrate the remarkable structural and photochemical versatility among phytochromes and CBCRs in driving light perception. A Photo-Labile Thioether Linkage to Phycoviolobilin Provides the Foundation for the Blue/Green Photocycles in DXCF-Cyanobacteriochromes.,Burgie ES, Walker JM, Phillips GN Jr, Vierstra RD Structure. 2013 Jan 8;21(1):88-97. doi: 10.1016/j.str.2012.11.001. Epub 2012 Dec , 6. PMID:23219880[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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