1dcw
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(New page: 200px<br /><applet load="1dcw" size="450" color="white" frame="true" align="right" spinBox="true" caption="1dcw, resolution 2.10Å" /> '''STRUCTURE OF A FOUR-...)
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Revision as of 00:51, 25 November 2007
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STRUCTURE OF A FOUR-WAY JUNCTION IN AN INVERTED REPEAT SEQUENCE.
Overview
Holliday junctions are important structural intermediates in, recombination, viral integration, and DNA repair. We present here the, single-crystal structure of the inverted repeat sequence d(CCGGTACCGG) as, a Holliday junction at the nominal resolution of 2. 1 A. Unlike the, previous crystal structures, this DNA junction has B-DNA arms with all, standard Watson-Crick base pairs; it therefore represents the intermediate, proposed by Holliday as being involved in homologous recombination. The, junction is in the stacked-X conformation, with two interconnected, duplexes formed by coaxially stacked arms, and is crossed at an angle of, 41.4 degrees as a right-handed X. A sequence comparison with previous, B-DNA and junction crystal structures shows that an ACC trinucleotide, forms the core of a stable junction in this system. The 3'-C x G base pair, of this ACC core forms direct and water-mediated hydrogen bonds to the, phosphates at the crossover strands. Interactions within this core define, the conformation of the Holliday junction, including the angle relating, the stacked duplexes and how the base pairs are stacked in the stable form, of the junction.
About this Structure
1DCW is a Protein complex structure of sequences from [1] with NA as ligand. Full crystallographic information is available from OCA.
Reference
The Holliday junction in an inverted repeat DNA sequence: sequence effects on the structure of four-way junctions., Eichman BF, Vargason JM, Mooers BH, Ho PS, Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):3971-6. PMID:10760268
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