View source for 7aer


==Rebuilt and re-refined PDB entry 5yep: tri-AMPylated Shewanella oneidensis HEPN toxin in complex with MNT antitoxin==
<StructureSection load='7aer' size='340' side='right'caption='[[7aer]], [[Resolution|resolution]] 3.00&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[7aer]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Shewanella_oneidensis_MR-1 Shewanella oneidensis MR-1]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7AER OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7AER 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]] 3&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=AMP:ADENOSINE+MONOPHOSPHATE'>AMP</scene>, <scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</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=7aer FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7aer OCA], [https://pdbe.org/7aer PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7aer RCSB], [https://www.ebi.ac.uk/pdbsum/7aer PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7aer ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MNTA_SHEON MNTA_SHEON] Antitoxin component of a type VII toxin-antitoxin (TA) system. Upon overexpression in situ or in E.coli neutralizes the effect of cognate toxin HepT (PubMed:26112399, PubMed:29555683, PubMed:33045733). Neutralization is mostly due to tri-AMPylation of toxin by this enzyme. Successively tri-AMPylates HepT on 'Tyr-104' (PubMed:33045733). Binds its own promoter, probably repressing its expression. The TA system confers plasmid stability in E.coli (PubMed:26112399).<ref>PMID:26112399</ref> <ref>PMID:29555683</ref> <ref>PMID:33045733</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Prokaryotic toxin-antitoxin (TA) systems are composed of a toxin capable of interfering with key cellular processes and its neutralizing antidote, the antitoxin. Here, we focus on the HEPN-MNT TA system encoded in the vicinity of a subtype I-D CRISPR-Cas system in the cyanobacterium Aphanizomenon flos-aquae. We show that HEPN acts as a toxic RNase, which cleaves off 4 nt from the 3' end in a subset of tRNAs, thereby interfering with translation. Surprisingly, we find that the MNT (minimal nucleotidyltransferase) antitoxin inhibits HEPN RNase through covalent di-AMPylation (diadenylylation) of a conserved tyrosine residue, Y109, in the active site loop. Furthermore, we present crystallographic snapshots of the di-AMPylation reaction at different stages that explain the mechanism of HEPN RNase inactivation. Finally, we propose that the HEPN-MNT system functions as a cellular ATP sensor that monitors ATP homeostasis and, at low ATP levels, releases active HEPN toxin.

HEPN-MNT Toxin-Antitoxin System: The HEPN Ribonuclease Is Neutralized by OligoAMPylation.,Songailiene I, Juozapaitis J, Tamulaitiene G, Ruksenaite A, Sulcius S, Sasnauskas G, Venclovas C, Siksnys V Mol Cell. 2020 Dec 17;80(6):955-970.e7. doi: 10.1016/j.molcel.2020.11.034. Epub, 2020 Dec 7. PMID:33290744<ref>PMID:33290744</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 7aer" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Large Structures]]
[[Category: Shewanella oneidensis MR-1]]
[[Category: Juozapaitis J]]
[[Category: Sasnauskas G]]
[[Category: Siksnys V]]
[[Category: Songailiene I]]
[[Category: Tamulaitiene G]]