View source for 6hpb


==Crystal structure of the E.coli HicAB toxin-antitoxin complex==
<StructureSection load='6hpb' size='340' side='right'caption='[[6hpb]], [[Resolution|resolution]] 2.28&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6hpb]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_2-222-05_S4_C3 Escherichia coli 2-222-05_S4_C3] and [https://en.wikipedia.org/wiki/Escherichia_coli_str._K-12_substr._MG1655 Escherichia coli str. K-12 substr. MG1655]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6HPB OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6HPB 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]] 2.28&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=MSE:SELENOMETHIONINE'>MSE</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</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=6hpb FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6hpb OCA], [https://pdbe.org/6hpb PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6hpb RCSB], [https://www.ebi.ac.uk/pdbsum/6hpb PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6hpb ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/HICA_ECOLI HICA_ECOLI] Toxic component of a type II toxin-antitoxin (TA) system. A probable translation-independent mRNA interferase. Overexpression causes cessation of cell growth and inhibits cell proliferation via inhibition of translation; this blockage is overcome (after 90 minutes) by subsequent expression of antitoxin HicB. Overexpression causes cleavage of a number of mRNAs and tmRNA, in a translation-independent fashion, suggesting this is an mRNA interferase (PubMed:19060138). mRNA interferases play a role in bacterial persistence to antibiotics (PubMed:21788497).<ref>PMID:19060138</ref> <ref>PMID:21788497</ref> 
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== Publication Abstract from PubMed ==
The E. coli hicAB type II toxin-antitoxin locus is unusual by being controlled by two promoters and by having the toxin encoded upstream of the antitoxin. HicA toxins contain a double-stranded RNA-binding fold and cleaves both mRNA and tmRNA in vivo, while HicB antitoxins contain a partial RNase H fold and either a helix-turn-helix (HTH) or ribbon-helix-helix domain. It is not known how an HTH DNA-binding domain affects higher-order structure for the HicAB modules. Here, we present crystal structures of the isolated E. coli HicB antitoxin and full-length HicAB complex showing that HicB forms a stable DNA-binding module and interacts in a canonical way with HicA despite the presence of an HTH-type DNA-binding domain. No major structural rearrangements take place upon binding of the toxin. Both structures expose well-ordered DNA-binding motifs allowing a model for DNA binding by the antitoxin to be generated.

The E. coli HicB Antitoxin Contains a Structurally Stable Helix-Turn-Helix DNA Binding Domain.,Manav MC, Turnbull KJ, Jurenas D, Garcia-Pino A, Gerdes K, Brodersen DE Structure. 2019 Sep 4. pii: S0969-2126(19)30279-5. doi:, 10.1016/j.str.2019.08.008. PMID:31495532<ref>PMID:31495532</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 6hpb" style="background-color:#fffaf0;"></div>
== References ==
<references/>
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</StructureSection>
[[Category: Escherichia coli 2-222-05_S4_C3]]
[[Category: Escherichia coli str. K-12 substr. MG1655]]
[[Category: Large Structures]]
[[Category: Brodersen DE]]
[[Category: Manav MC]]