View source for 4ijg


==Crystal structure of monomeric bacteriophytochrome==
<StructureSection load='4ijg' size='340' side='right'caption='[[4ijg]], [[Resolution|resolution]] 1.70&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ijg]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Deinococcus_radiodurans_R1 Deinococcus radiodurans R1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4IJG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4IJG 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]] 1.701&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=GOL:GLYCEROL'>GOL</scene>, <scene name='pdbligand=LBV:3-[2-[(Z)-[3-(2-CARBOXYETHYL)-5-[(Z)-(4-ETHENYL-3-METHYL-5-OXIDANYLIDENE-PYRROL-2-YLIDENE)METHYL]-4-METHYL-PYRROL-1-IUM-2-YLIDENE]METHYL]-5-[(Z)-[(3E)-3-ETHYLIDENE-4-METHYL-5-OXIDANYLIDENE-PYRROLIDIN-2-YLIDENE]METHYL]-4-METHYL-1H-PYRROL-3-YL]PROPANOIC+ACID'>LBV</scene>, <scene name='pdbligand=PEG:DI(HYDROXYETHYL)ETHER'>PEG</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=4ijg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ijg OCA], [https://pdbe.org/4ijg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ijg RCSB], [https://www.ebi.ac.uk/pdbsum/4ijg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ijg ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/BPHY_DEIRA BPHY_DEIRA] Photoreceptor which exists in two forms that are reversibly interconvertible by light: the R form that absorbs maximally in the red region of the spectrum and the FR form that absorbs maximally in the far-red region. Has also a slight blue shift for the far-red maximum. Could also absorb green light. May participate in regulating pigment synthesis like the carotenoid deinoxanthin which could protect the bacterium from intense visible light.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Use of fluorescent proteins to study in vivo processes in mammals requires near-infrared (NIR) biomarkers that exploit the ability of light in this range to penetrate tissue. Bacteriophytochromes (BphPs) are photoreceptors that couple absorbance of NIR light to photoisomerization, protein conformational changes and signal transduction. BphPs have been engineered to form NIR fluorophores, including IFP1.4, Wi-Phy, and iRFP, initially by replacement of Asp207 by His. This position was suggestive because its main chain carbonyl is within hydrogen-bonding distance to pyrrole ring nitrogens of the biliverdin chromophore, thus potentially functioning as a crucial proton sink during photoconversion. In order to explain the origin of fluorescence in these phytofluors, we solved the crystal structures of IFP1.4 and a comparison non-fluorescent monomeric phytochrome DrCBDmon. Met186 and Val288 in IFP1.4 are responsible for the formation of a tightly packed hydrophobic hub around the biliverdin D ring. Met186 is also responsible for the blue-shifted IFP1.4 excitation maximum relative to the parent BphP. The structure of IFP1.4 revealed decreased structural heterogeneity and a contraction of two surface regions as direct consequences of side chain substitutions. Unexpectedly, IFP1.4 with Asp207 reinstalled (IFPrev) has a higher fluorescence quantum yield (~9%) than any NIR phytofluor published to date. In agreement, fluorescence lifetime measurements confirm the exceptionally long excited state lifetimes, up to 815 ps, in IFP1.4 and IFPrev. Our research helps delineate the origin of fluorescence in engineered BphPs, and will facilitate the widespread adoption of phytofluors as biomarkers.

Origins of Fluorescence in Evolved Bacteriophytochromes.,Bhattacharya S, Auldridge ME, Lehtivuori H, Ihalainen JA, Forest KT J Biol Chem. 2014 Sep 24. pii: jbc.M114.589739. PMID:25253687<ref>PMID:25253687</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4ijg" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Deinococcus radiodurans R1]]
[[Category: Large Structures]]
[[Category: Auldridge ME]]