1k2l
From Proteopedia
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STRUCTURAL CHARACTERIZATION OF BISINTERCALATION IN HIGHER-ORDER DNA AT A JUNCTION-LIKE QUADRUPLEX
Overview
We report the single-crystal X-ray structure for the complex of the, bisacridine, bis-(9-aminooctyl(2-(dimethylaminoethyl)acridine-4-carboxamide)) with the, oligonucleotide d(CGTACG)(2) to a resolution of 2.4A. Solution studies, with closed circular DNA show this compound to be a bisintercalating, threading agent, but so far we have no crystallographic or NMR structural, data conforming to the model of contiguous intercalation within the same, duplex. Here, with the hexameric duplex d(CGTACG), the DNA is observed to, undergo a terminal cytosine base exchange to yield an unusual guanine, quadruplex intercalation site through which the bisacridine threads its, octamethylene linker to fuse two DNA duplexes. The 4-carboxamide, side-chains form anchoring hydrogen-bonding interactions with guanine O6, atoms on each side of the quadruplex. This higher-order DNA structure, provides insight into an unexpected property of bisintercalating threading, agents, and suggests the idea of targeting such compounds specifically at, four-way DNA junctions.
About this Structure
1K2L is a Protein complex structure of sequences from [1] with BDC and CO as ligands. Full crystallographic information is available from OCA.
Reference
Structural characterisation of bisintercalation in higher-order DNA at a junction-like quadruplex., Teixeira SC, Thorpe JH, Todd AK, Powell HR, Adams A, Wakelin LP, Denny WA, Cardin CJ, J Mol Biol. 2002 Oct 18;323(2):167-71. PMID:12381312
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