1k8p

<table><tr><td colspan='2'>[[1k8p]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1K8P OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1K8P FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=K:POTASSIUM+ION'>K</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene></td></tr>

<tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><scene name='pdbligand=BRU:5-BROMO-2-DEOXYURIDINE-5-MONOPHOSPHATE'>BRU</scene></td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1k8p FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1k8p OCA], [http://pdbe.org/1k8p PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=1k8p RCSB], [http://www.ebi.ac.uk/pdbsum/1k8p PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=1k8p ProSAT]</span></td></tr>

<div style="background-color:#fffaf0;">

== Publication Abstract from PubMed ==

Telomeric ends of chromosomes, which comprise noncoding repeat sequences of guanine-rich DNA, are fundamental in protecting the cell from recombination and degradation. Disruption of telomere maintenance leads to eventual cell death, which can be exploited for therapeutic intervention in cancer. Telomeric DNA sequences can form four-stranded (quadruplex) structures, which may be involved in the structure of telomere ends. Here we describe the crystal structure of a quadruplex formed from four consecutive human telomeric DNA repeats and grown at a K(+) concentration that approximates its intracellular concentration. K(+) ions are observed in the structure. The folding and appearance of the DNA in this intramolecular quadruplex is fundamentally different from the published Na(+)-containing quadruplex structures. All four DNA strands are parallel, with the three linking trinucleotide loops positioned on the exterior of the quadruplex core, in a propeller-like arrangement. The adenine in each TTA linking trinucleotide loop is swung back so that it intercalates between the two thymines. This DNA structure suggests a straightforward path for telomere folding and unfolding, as well as ways in which it can recognize telomere-associated proteins.

Crystal structure of parallel quadruplexes from human telomeric DNA.,Parkinson GN, Lee MP, Neidle S Nature. 2002 Jun 20;417(6891):876-80. Epub 2002 May 26. PMID:12050675<ref>PMID:12050675</ref>

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

</div>

<div class="pdbe-citations 1k8p" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Lee, M P.H]]

[[Category: Neidle, S]]

[[Category: Parkinson, G N]]

[[Category: Quadruplex dna]]