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.
(2001) Acta Crystallogr.,Sect.D 57: 1609-1613
- PubMed: 11679725
- Primary Citation of Related Structures:
- PubMed Abstract:
- Structure of a Mispaired RNA Double Helix at 1.6 A Resolution and Implications for the Prediction of RNA Secondary Structure
Cruse, W.B.,Saludjian, P.,Biala, E.,Strazewski, P.,Prange, T.,Kennard, O.
(1994) Proc.Natl.Acad.Sci.USA 91: 4160
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 derivati ...
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.
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