1xwr

<table><tr><td colspan='2'>[[1xwr]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Bacteriophage_lambda Bacteriophage lambda]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1XWR OCA]. For a <b>guided tour on the structure components</b> use [http://proteopedia.org/fgij/fg.htm?mol=1XWR FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=IPA:ISOPROPYL+ALCOHOL'>IPA</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">CII ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=10710 Bacteriophage lambda])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://proteopedia.org/fgij/fg.htm?mol=1xwr FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1xwr OCA], [http://pdbe.org/1xwr PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1xwr RCSB], [http://www.ebi.ac.uk/pdbsum/1xwr PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1xwr ProSAT]</span></td></tr>

[[http://www.uniprot.org/uniprot/RPC2_LAMBD RPC2_LAMBD]] This protein and protein CIII form a complex that is involved in the initiation of lysogeny. The complex binds at either of the cy regulatory sites preceding the CI repressor protein and integrase coding regions and induces transcription of these genes.

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== Publication Abstract from PubMed ==

The temperate coliphage lambda, after infecting its host bacterium Escherichia coli, can develop either along the lytic or the lysogenic pathway. Crucial to the lysis/lysogeny decision is the homotetrameric transcription-activator protein CII (4 x 11 kDa) of the phage that binds to a unique direct-repeat sequence T-T-G-C-N6-T-T-G-C at each of the three phage promoters it activates: p(E), p(I), and p(aQ). Several regions of CII have been identified for its various functions (DNA binding, oligomerization, and susceptibility to host protease), but the crystal structure of the protein long remained elusive. Here, we present the three-dimensional structure of CII at 2.6-angstroms resolution. The CII monomer is comprised of four alpha helices and a disordered C terminus. The first three helices (alpha1-alpha3) form a compact domain, whereas the fourth helix (alpha4) protrudes in different orientations in each subunit. A four-helix bundle, formed by alpha4 from each subunit, holds the tetramer. The quaternary structure can be described as a dimer of dimers, but the tetramer does not exhibit a closed symmetry. This unusual quaternary arrangement allows the placement of the helix-turn-helix motifs of two of the four CII subunits for interaction with successive major grooves of B-DNA, from one face of DNA. This structure provides a simple explanation for how a homotetrameric protein may recognize a direct-repeat DNA sequence rather than the inverted-repeat sequences of most prokaryotic activators.

Structure of lambda CII: implications for recognition of direct-repeat DNA by an unusual tetrameric organization.,Datta AB, Panjikar S, Weiss MS, Chakrabarti P, Parrack P Proc Natl Acad Sci U S A. 2005 Aug 9;102(32):11242-7. Epub 2005 Aug 1. PMID:16061804<ref>PMID:16061804</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>

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== References ==

<references/>

[[Category: Bacteriophage lambda]]

[[Category: Chakrabarti, P]]

[[Category: Datta, A B]]

[[Category: Panjikar, S]]

[[Category: Parrack, P]]

[[Category: Weiss, M S]]

[[Category: Dna binding protein]]