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== Function == | == Function == | ||
[https://www.uniprot.org/uniprot/Q8DLC7_THEVB Q8DLC7_THEVB] | [https://www.uniprot.org/uniprot/Q8DLC7_THEVB Q8DLC7_THEVB] | ||
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== 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> | |||
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<div class="pdbe-citations 4glq" style="background-color:#fffaf0;"></div> | |||
==See Also== | ==See Also== | ||
*[[Chemotaxis protein 3D structures|Chemotaxis protein 3D structures]] | *[[Chemotaxis protein 3D structures|Chemotaxis protein 3D structures]] | ||
== References == | |||
<references/> | |||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> |
Latest revision as of 13:02, 30 October 2024
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
FunctionPublication 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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