117d
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(New page: 200px<br /><applet load="117d" size="450" color="white" frame="true" align="right" spinBox="true" caption="117d, resolution 2.550Å" /> '''CRYSTAL AND MOLECUL...)
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Revision as of 19:39, 24 November 2007
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CRYSTAL AND MOLECULAR STRUCTURE OF THE ALTERNATING DODECAMER D(GCGTACGTACGC) IN THE A-DNA FORM: COMPARISON WITH THE ISOMORPHOUS NON-ALTERNATING DODECAMER D(CCGTACGTACGG)
Overview
The crystal structure of the alternating dodecamer d(GCGTACGTACGC) (5'-GC), has been determined to a resolution of 2.55A using oscillation film data., The crystals belong to space group P6(1) 22, a = b = 46.2A, c = 71.5A with, one strand in the asymmetric unit, and are isomorphous with a previously, described non-alternating dodecamer, d(CCGTACGTACGG) (5'-CC). Refinement, by X-PLOR/NUCLSQ gave a final R factor of 14.2% for 1089 observations. The, molecule adopts the A-DNA form. The interchange of the terminal base pairs, in the two dodecamers results in differences in the intermolecular, contacts and may account for the differences in the bending. This, dodecamer shows an axial deflection of 30 degrees, in the direction of the, major groove compared to 20 degrees in 5'-CC and may be a consequence of, additional contacts generated in 5'-GC by the interchange of end base, pairs. The high helical axis deflection appreciably influences the local, helical parameters. The molecule exhibits relatively high inclination, angles, and has a narrow major groove. The helical parameters when, described relative to the dyad-related hexamer halves of the molecule give, more reasonable values. The crystal packing, local helical parameters, torsion angles, and hydration are described and also compared with the, non-alternating 5'-CC dodecamer.
About this Structure
117D is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.
Reference
Crystal and molecular structure of the alternating dodecamer d(GCGTACGTACGC) in the A-DNA form: comparison with the isomorphous non-alternating dodecamer d(CCGTACGTACGG)., Bingman C, Jain S, Zon G, Sundaralingam M, Nucleic Acids Res. 1992 Dec 25;20(24):6637-47. PMID:1480485
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