View source for 1kca


==Crystal Structure of the lambda Repressor C-terminal Domain Octamer==
<StructureSection load='1kca' size='340' side='right'caption='[[1kca]], [[Resolution|resolution]] 2.91&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1kca]] is a 8 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_virus_Lambda Escherichia virus Lambda]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KCA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KCA 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]] 2.91&#8491;</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=1kca FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kca OCA], [https://pdbe.org/1kca PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kca RCSB], [https://www.ebi.ac.uk/pdbsum/1kca PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kca ProSAT]</span></td></tr>
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== Function ==
[https://www.uniprot.org/uniprot/RPC1_LAMBD RPC1_LAMBD] Repressor protein CI allows phage lambda to reside inactively in the chromosome of its host bacterium. This lysogenic state is maintained by binding of regulatory protein CI to the OR and OL operators, preventing transcription of proteins necessary for lytic development.
== 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/kc/1kca_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=1kca ConSurf].
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== Publication Abstract from PubMed ==
The three-dimensional structure of the lambda repressor C-terminal domain (CTD) has been determined at atomic resolution. In the crystal, the CTD forms a 2-fold symmetric tetramer that mediates cooperative binding of two repressor dimers to pairs of operator sites. Based upon this structure, a model was proposed for the structure of an octameric repressor that forms both in the presence and absence of DNA. Here, we have determined the structure of the lambda repressor CTD in three new crystal forms, under a wide variety of conditions. All crystals have essentially the same tetramer, confirming the results of the earlier study. One crystal form has two tetramers bound to form an octamer, which has the same overall architecture as the previously proposed model. An unexpected feature of the octamer in the crystal structure is a unique interaction at the tetramer-tetramer interface, formed by residues Gln209, Tyr210 and Pro211, which contact symmetry-equivalent residues from other subunits of the octamer. Interestingly, these residues are also located at the dimer-dimer interface, where the specific interactions are different. The structures thus indicate specific amino acid residues that, at least in principle, when altered could result in repressors that form tetramers but not octamers.

Crystal structure of the lambda repressor C-terminal domain octamer.,Bell CE, Lewis M J Mol Biol. 2001 Dec 14;314(5):1127-36. PMID:11743728<ref>PMID:11743728</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Escherichia virus Lambda]]
[[Category: Large Structures]]
[[Category: Bell CE]]
[[Category: Lewis M]]