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An efficient method for solving RNA structures: MAD phasing by replacing magnesium with zinc.

E Ennifar·P Walter·P Dumas
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Abstract

The structure of a 46-nucleotide RNA complex has been successfully solved using multi-wavelength anomalous dispersion (MAD) at the zinc K edge. Taking advantage of the eight magnesium-binding sites, it has been shown that for five of them magnesium could be replaced by zinc. This resulted in an excellent 2.0 A MAD electron-density map. Zinc, in common with some other transition metals, is able to replace magnesium in RNA structures, but zinc has the advantage of its K edge being ideally located at 1.284 A. As most RNA molecules contain magnesium-binding sites, it is suggested that this method could be a valuable alternative to the use of bromo derivatives of bases, which is limited to chemically synthesizable and thus rather short RNA sequences.

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Crystallography, X-RayElectronsMagnesiumModels, MolecularNucleic Acid ConformationRNAZincJournal ArticleResearch Support, Non-U.S. Gov't

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E Ennifar, P Walter, P Dumas. 2001. An efficient method for solving RNA structures: MAD phasing by replacing magnesium with zinc.. https://doi.org/10.1107/s0907444900017558

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