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1ue4
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(New page: 200px<br /><applet load="1ue4" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ue4, resolution 1.65Å" /> '''Crystal structure of...)
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Revision as of 01:43, 25 November 2007
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Crystal structure of d(GCGAAAGC)
Overview
The DNA fragments d(GCGAAGC) and d(GCGAAAGC) are known to exhibit several, extraordinary properties. Their crystal structures have been determined at, 1.6 and 1.65 A resolution, respectively. Two heptamers aligned in an, antiparallel fashion associate to form a duplex having molecular twofold, symmetry. In the crystallographic asymmetric unit, there are three, structurally identical duplexes. At both ends of each duplex, two, Watson-Crick G.C pairs constitute the stem regions. In the central part, two sheared G.A pairs are crossed and stacked on each other, so that the, stacked two guanine bases of the G.AxA.G crossing expose their, Watson-Crick and major-groove sites into solvent, suggesting a functional, role. The adenine moieties of the A(5) residues are inside the duplex, wedged between the A(4) and G(6) residues, but there are no partners for, interactions. To close the open space on the counter strand, the duplex is, strongly bent. In the asymmetric unit of the d(GCGAAAGC) crystal, (tetragonal form), there is only one octamer chain. However, the two, chains related by the crystallographic twofold symmetry associate to form, an antiparallel duplex, similar to the base-intercalated duplex found in, the hexagonal crystal form of the octamer. It is interesting to note that, the significant difference between the present bulge-in structure of, d(GCGAAGC) and the base-intercalated duplex of d(GCGAAAGC) can be ascribed, to a switching of partners of the sheared G.A pairs.
About this Structure
1UE4 is a Protein complex structure of sequences from [1] with MG as ligand. Full crystallographic information is available from OCA.
Reference
Structures of d(GCGAAGC) and d(GCGAAAGC) (tetragonal form): a switching of partners of the sheared G.A pairs to form a functional G.AxA.G crossing., Sunami T, Kondo J, Hirao I, Watanabe K, Miura K, Takenaka A, Acta Crystallogr D Biol Crystallogr. 2004 Mar;60(Pt 3):422-31. Epub 2004, Feb 25. PMID:14993665
Page seeded by OCA on Sun Nov 25 03:51:00 2007
Categories: Protein complex | Hirao, I. | Kondo, J. | Miura, K. | Sunami, T. | Takenaka, A. | Watanabe, K. | MG | Bulge-in duplex | Dna | G:axa:g crossing | Sheared g:a pair
