View source for 2h3c


==Structural basis for nucleic acid and toxin recognition of the bacterial antitoxin CcdA==
<StructureSection load='2h3c' size='340' side='right'caption='[[2h3c]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2h3c]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2H3C OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2H3C FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR</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=2h3c FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2h3c OCA], [https://pdbe.org/2h3c PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2h3c RCSB], [https://www.ebi.ac.uk/pdbsum/2h3c PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2h3c ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CCDA_ECOLI CCDA_ECOLI] Antitoxin component of a toxin-antitoxin (TA) module which inhibits the post-segregational killing (PSK) of plasmid-free cells, also referred to as a plasmid addiction system. Labile antitoxin with a half-life of about 1 hour in the presence of CcdB. Binds to and blocks the activity of CcdB; will also remove bound CcdB protein from the CcdB-GyrA complex by forming a CcdA-CcdB complex, a process termed rejuvenation. The N-terminal 36 residues are not required for rejuventation. Functions as a transcriptional corepressor for the ccdAB operon, repression also requires CcdB.<ref>PMID:6327993</ref> <ref>PMID:2651399</ref> <ref>PMID:6308648</ref> <ref>PMID:2615761</ref> <ref>PMID:1324324</ref> <ref>PMID:8604132</ref> <ref>PMID:19647513</ref> 
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/h3/2h3c_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2h3c ConSurf].
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== Publication Abstract from PubMed ==
Toxin-antitoxin systems are highly abundant in plasmids and bacterial chromosomes. They ensure plasmid maintenance by killing bacteria that have lost the plasmid. Their expression is autoregulated at the level of transcription. Here, we present the solution structure of CcdA, the antitoxin of the ccd system, as a free protein (16.7 kDa) and in complex with its cognate DNA (25.3 kDa). CcdA is composed of two distinct and independent domains: the N-terminal domain, responsible for DNA binding, which establishes a new family of the ribbon-helix-helix fold and the C-terminal region, which is responsible for the interaction with the toxin CcdB. The C-terminal domain is intrinsically unstructured and forms a tight complex with the toxin. We show that CcdA specifically recognizes a 6 bp palindromic DNA sequence within the operator-promoter (OP) region of the ccd operon and binds to DNA by insertion of the positively charged N-terminal beta-sheet into the major groove. The binding of up to three CcdA dimers to a 33mer DNA of its operator-promoter region was studied by NMR spectroscopy, isothermal titration calorimetry and single point mutation. The highly flexible C-terminal region of free CcdA explains its susceptibility to proteolysis by the Lon ATP-dependent protease.

Structural basis for nucleic acid and toxin recognition of the bacterial antitoxin CcdA.,Madl T, Van Melderen L, Mine N, Respondek M, Oberer M, Keller W, Khatai L, Zangger K J Mol Biol. 2006 Nov 24;364(2):170-85. Epub 2006 Sep 1. PMID:17007877<ref>PMID:17007877</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Keller W]]
[[Category: Madl T]]
[[Category: Oberer M]]
[[Category: Respondek M]]
[[Category: Van Melderen L]]
[[Category: Zangger K]]