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Structure of Poly (U).poly (A).poly (U).

R Chandrasekaran·A Giacometti·S Arnott
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Abstract

The molecular structure of poly (U).poly (A).poly (U) has been determined and refined using the continuous x-ray intensity data on layer lines in the diffraction pattern obtained from an oriented fiber of the RNA. The final R-value for the preferred structure is 0.24, far lower than that for the plausible alternatives. The polymer forms an 11-fold right-handed triple-helix of pitch 33.5A and each base triplet is stabilized by Crick-Watson-Hoogsteen hydrogen bonds. The ribose rings in the three strands have C3'-endo, C2'-endo and C2'-endo conformations, respectively. The helix derives additional stability through systematic interchain hydrogen bonds involving ribose hydroxyls and uracil bases. The relatively grooveless cylindrical shape of the triple-helix is consistent with the lack of lateral organization.

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DNAHydrogen BondingModels, MolecularModels, StatisticalNucleic Acid ConformationPoly APoly URiboseX-Ray DiffractionJournal ArticleResearch Support, Non-U.S. Gov't

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R Chandrasekaran, A Giacometti, S Arnott. 2000. Structure of Poly (U).poly (A).poly (U).. https://doi.org/10.1080/07391102.2000.10506590

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