1iha
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(New page: 200px<br /><applet load="1iha" size="450" color="white" frame="true" align="right" spinBox="true" caption="1iha, resolution 1.60Å" /> '''Structure of the Hyb...)
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Revision as of 19:53, 24 November 2007
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Structure of the Hybrid RNA/DNA R-GCUUCGGC-D[BR]U in Presence of RH(NH3)6+++
Overview
In the presence of cobalt, rhodium or iridium hexammine salts, the RNA/DNA, hybrid r-GCUUCGGC-d(X)U (with X = F, Cl or Br) crystallizes as a, double-stranded helix with four consecutive G-U and C-U mismatches. The, deoxy chloro- and bromouracil derivatives are isomorphous, space group C2, unit-cell parameters a = 53.80, b = 19.40, c = 50.31 A, beta = 109.9, degrees, with the same infinite helix arrangement in the packing along the, c axis with one extra DNA halogenouracil base included in the stacking., However, the fluorouracil derivative, with unit-cell parameters a = 53.75, b = 19.40, c = 45.84 A, beta = 105.7 degrees, is not isomorphous. The, corresponding extra DNA base d(F)U of the second strand is ejected out of, the helical stack, leading to a shortening of the c axis. The specific, destabilization of the fluorouracil for the duplex building is analyzed in, terms of the polarization effect of the halogen atom attached to the, 3'-terminal base that modulates its interactions.
About this Structure
1IHA is a Protein complex structure of sequences from [1] with RHD and CL as ligands. Full crystallographic information is available from OCA.
Reference
Destabilizing effect of a fluorouracil extra base in a hybrid RNA duplex compared with bromo and chloro analogues., Cruse W, Saludjian P, Neuman A, Prange T, Acta Crystallogr D Biol Crystallogr. 2001 Nov;57(Pt 11):1609-13. Epub 2001, Oct 25. PMID:11679725
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