View source for 2bjc


==NMR structure of a protein-DNA complex of an altered specificity mutant of the lac repressor headpiece that mimics the gal repressor==
<StructureSection load='2bjc' size='340' side='right'caption='[[2bjc]]' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2bjc]] 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=2BJC OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2BJC FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Solution NMR, 16 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=2bjc FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2bjc OCA], [https://pdbe.org/2bjc PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2bjc RCSB], [https://www.ebi.ac.uk/pdbsum/2bjc PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2bjc 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/bj/2bjc_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=2bjc ConSurf].
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== Publication Abstract from PubMed ==
Recognition of the lac operator by the lac repressor involves specific interactions between residues in the repressor's recognition helix and bases in the DNA major groove. Tyr17 and Gln18, at positions 1 and 2 in the lac repressor recognition helix, can be exchanged for other amino acids to generate mutant repressors that display altered specificity. We have solved the solution structure of a protein-DNA complex of an altered-specificity mutant lac headpiece in which Tyr17 and Gln18 were exchanged for valine and alanine, respectively, as found in the recognition helix of the gal repressor. As previously described by Lehming et al. (EMBO J. 1987, 6, 3145-3153), this altered-specificity mutant of the lac repressor recognizes a variant lac operator that is similar to the gal operator Oe. The mutant lac headpiece showed the predicted specificity and is also able to mimic the gal repressor by recognizing and bending the natural gal operator Oe. These structural data show that, while most of the anchoring points that help the lac headpiece to assemble on the lac operator were preserved, a different network of protein-DNA interactions connecting Ala17 and Val18 to bases in the DNA major groove drives the specificity towards the altered operator.

Altered specificity in DNA binding by the lac repressor: a mutant lac headpiece that mimics the gal repressor.,Kopke Salinas R, Folkers GE, Bonvin AM, Das D, Boelens R, Kaptein R Chembiochem. 2005 Sep;6(9):1628-37. PMID:16094693<ref>PMID:16094693</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 2bjc" style="background-color:#fffaf0;"></div>

==See Also==
*[[Lac repressor|Lac repressor]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Boelens R]]
[[Category: Bonvin AMJJ]]
[[Category: Das D]]
[[Category: Folkers GE]]
[[Category: Kaptein R]]
[[Category: Salinas RK]]