View source for 2kej


==Solution structure of a dimer of LAC repressor DNA-binding domain complexed to its natural operator O2==
<StructureSection load='2kej' size='340' side='right'caption='[[2kej]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2kej]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli_K-12 Escherichia coli K-12]. Full experimental information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2KEJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2KEJ FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 20 models</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=2kej FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2kej OCA], [https://pdbe.org/2kej PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2kej RCSB], [https://www.ebi.ac.uk/pdbsum/2kej PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2kej ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/LACI_ECOLI LACI_ECOLI] Repressor of the lactose operon. Binds allolactose as an inducer.
== 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/ke/2kej_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=2kej ConSurf].
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== Publication Abstract from PubMed ==
The structures of a dimeric mutant of the Lac repressor DNA-binding domain complexed with the auxiliary operators O2 and O3 have been determined using NMR spectroscopy and compared to the structures of the previously determined Lac-O1 and Lac-nonoperator complexes. Structural analysis of the Lac-O1 and Lac-O2 complexes shows highly similar structures with very similar numbers of specific and nonspecific contacts, in agreement with similar affinities for these two operators. The left monomer of the Lac repressor in the Lac-O3 complex retains most of these specific contacts. However, in the right half-site of the O3 operator, there is a significant loss of protein-DNA contacts, explaining the low affinity of the Lac repressor for the O3 operator. The binding mode in the right half-site resembles that of the nonspecific complex. In contrast to the Lac-nonoperator DNA complex where no hinge helices are formed, the stability of the hinge helices in the weak Lac-O3 complex is the same as in the Lac-O1 and Lac-O2 complexes, as judged from the results of hydrogen/deuterium experiments.

Specificity and affinity of Lac repressor for the auxiliary operators O2 and O3 are explained by the structures of their protein-DNA complexes.,Romanuka J, Folkers GE, Biris N, Tishchenko E, Wienk H, Bonvin AM, Kaptein R, Boelens R J Mol Biol. 2009 Jul 17;390(3):478-89. Epub 2009 May 18. PMID:19450607<ref>PMID:19450607</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 2kej" style="background-color:#fffaf0;"></div>

==See Also==
*[[Lac repressor|Lac repressor]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli K-12]]
[[Category: Large Structures]]
[[Category: Biris N]]
[[Category: Boelens R]]
[[Category: Folkers G]]
[[Category: Kaptein R]]
[[Category: Romanuka J]]
[[Category: Tishchenko E]]
[[Category: Wienk H]]