View source for 7u55


==Crystal structure of Thermoplasmatales archaeon heliorhodopsin at pH 4.5==
<StructureSection load='7u55' size='340' side='right'caption='[[7u55]], [[Resolution|resolution]] 1.97&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7u55]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Thermoplasmatales_archaeon_SG8-52-1 Thermoplasmatales archaeon SG8-52-1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7U55 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7U55 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]] 1.97&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CL:CHLORIDE+ION'>CL</scene>, <scene name='pdbligand=D12:DODECANE'>D12</scene>, <scene name='pdbligand=RET:RETINAL'>RET</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=7u55 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7u55 OCA], [https://pdbe.org/7u55 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7u55 RCSB], [https://www.ebi.ac.uk/pdbsum/7u55 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7u55 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/A0A151EDA9_9ARCH A0A151EDA9_9ARCH] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Within the microbial rhodopsin family, heliorhodopsins (HeRs) form a phylogenetically distinct group of light-harvesting retinal proteins with largely unknown functions. We have determined the 1.97 A resolution X-ray crystal structure of Thermoplasmatales archaeon SG8-52-1 heliorhodopsin (TaHeR) in the presence of NaCl under acidic conditions (pH 4.5), which complements the known 2.4 A TaHeR structure acquired at pH 8.0. The low pH structure revealed that the hydrophilic Schiff base cavity (SBC) accommodates a chloride anion to stabilize the protonated retinal Schiff base when its primary counterion (Glu-108) is neutralized. Comparison of the two structures at different pH revealed conformational changes connecting the SBC and the extracellular loop linking helices A-B. We corroborated this intramolecular signaling transduction pathway with computational studies, which revealed allosteric network changes propagating from the perturbed SBC to the intracellular and extracellular space, suggesting TaHeR may function as a sensory rhodopsin. This intramolecular signaling mechanism may be conserved among HeRs, as similar changes were observed for HeR 48C12 between its pH 8.8 and pH 4.3 structures. We additionally performed DEER experiments, which suggests that TaHeR forms possible dimer-of-dimer associations which may be integral to its putative functionality as a light sensor in binding a transducer protein.

Low pH structure of heliorhodopsin reveals chloride binding site and intramolecular signaling pathway.,Besaw JE, Reichenwallner J, De Guzman P, Tucs A, Kuo A, Morizumi T, Tsuda K, Sljoka A, Miller RJD, Ernst OP Sci Rep. 2022 Aug 17;12(1):13955. doi: 10.1038/s41598-022-17716-9. PMID:35977989<ref>PMID:35977989</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7u55" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Thermoplasmatales archaeon SG8-52-1]]
[[Category: Besaw JE]]
[[Category: De Guzman P]]
[[Category: Ernst OP]]
[[Category: Miller RJD]]