View source for 8g9z


==High-resolution crystal structure of the human selenomethionine-derived SepSecS-tRNASec complex==
<StructureSection load='8g9z' size='340' side='right'caption='[[8g9z]], [[Resolution|resolution]] 2.07&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8g9z]] is a 5 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8G9Z OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8G9Z 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]] 2.07&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MPD:(4S)-2-METHYL-2,4-PENTANEDIOL'>MPD</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=PLR:(5-HYDROXY-4,6-DIMETHYLPYRIDIN-3-YL)METHYL+DIHYDROGEN+PHOSPHATE'>PLR</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=8g9z FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8g9z OCA], [https://pdbe.org/8g9z PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8g9z RCSB], [https://www.ebi.ac.uk/pdbsum/8g9z PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8g9z ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/SPCS_HUMAN SPCS_HUMAN] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
O-Phosphoseryl-tRNASec selenium transferase (SepSecS) catalyzes the terminal step of selenocysteine (Sec) synthesis in archaea and eukaryotes. How the Sec synthetic machinery recognizes and discriminates tRNASec from the tRNA pool is essential to the integrity of the selenoproteome. Previously, we suggested that SepSecS adopts a competent conformation that is pre-ordered for catalysis. Herein, using high-resolution X-ray crystallography, we visualized tRNA-dependent conformational changes in human SepSecS that may be a prerequisite for achieving catalytic competency. We show that tRNASec binding organizes the active sites of the catalytic protomer, while stabilizing the N- and C-termini of the non-catalytic protomer. Binding of large anions to the catalytic groove may further optimize the catalytic site for substrate binding and catalysis. Our biochemical and mutational analyses demonstrate that productive SepSecS*tRNASec complex formation is enthalpically driven and primarily governed by electrostatic interactions between the acceptor-, TPsiC-, and variable arms of tRNASec and helices alpha1 and alpha14 of SepSecS. The detailed visualization of the tRNA-dependent activation of SepSecS provides a structural basis for a revised model of the terminal reaction of Sec formation in archaea and eukaryotes.

Structural basis for the tRNA-dependent activation of the terminal complex of selenocysteine synthesis in humans.,Puppala AK, Castillo Suchkou J, French RL, Kiernan KA, Simonovic M Nucleic Acids Res. 2023 May 8;51(8):4012-4026. doi: 10.1093/nar/gkad182. PMID:36929010<ref>PMID:36929010</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8g9z" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Castillo Suchkou J]]
[[Category: Puppala A]]
[[Category: Simonovic M]]