263d

<StructureSection load='263d' size='340' side='right' caption='[[263d]], [[Resolution|resolution]] 2.20&Aring;' scene=''>

<table><tr><td colspan='2'>[[263d]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=263D OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=263D FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=TBZ:2-(4-METHOXYPHENYL)-5-(3-AMINO-1-PYRROLIDINYL)-2,5,2,5-TRI-BENZIMIDAZOLE'>TBZ</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=263d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=263d OCA], [http://www.rcsb.org/pdb/explore.do?structureId=263d RCSB], [http://www.ebi.ac.uk/pdbsum/263d PDBsum]</span></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure is reported of a tris(benzimidazole) analogue of the minor-groove drug Hoechst 33258 bound to the sequence d(CGCAAATTTGCG)2. The structure has been refined to an R factor of 17.4% at a resolution of 2.2 A. The ligand covers approximately 7 1/2 base pairs, including the 5'-AAATTT central sequence. This has an exceptionally narrow minor-groove width, together with high propeller twists for individual base pairs. The ligand has a highly twisted structure, with an overall twist of 50 degrees between aromatic rings. All three benzimidazole subunits are in register with the DNA, and there is a symmetric group of six hydrogen bonds between ligand and A.T base-pair edges. By contrast, the ligand does not show an optimal isohelical fit to the DNA. The correct phasing of drug and DNA base pairs is ensured by a number of changes to the DNA such that the central 5'-AAATTT region is slightly unwound relative to the structures of other noncovalent minor-groove drug complexes.

Isohelicity and phasing in drug--DNA sequence recognition: crystal structure of a tris(benzimidazole)--oligonucleotide complex.,Clark GR, Gray EJ, Neidle S, Li YH, Leupin W Biochemistry. 1996 Oct 29;35(43):13745-52. PMID:8901516<ref>PMID:8901516</ref>

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

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== References ==

<references/>

[[Category: Clark, G R.]]

[[Category: Gray, E J.]]

[[Category: Leupin, W.]]

[[Category: Li, Y H.]]

[[Category: Neidle, S.]]

[[Category: Double helix]]