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The ultra-high resolution structure of d(CTTTTAAAAG)2: modulation of bending by T-A steps and its role in DNA recognitionThe ultra-high resolution structure of d(CTTTTAAAAG)2: modulation of bending by T-A steps and its role in DNA recognition
Structural highlights
Publication Abstract from PubMedFor the first time, ab initio direct methods have been used to solve the crystal structure of an RNA/DNA hybrid decamer. The RNA/DNA sequence corresponds to the leftmost two-thirds of the polypurine tract (PPT), the primer for second-strand DNA synthesis by HIV-1 reverse transcriptase (RT). Direct methods using Shake-and-Bake (SnB) yielded solutions for the RNA/DNA decamer molecule using 1.15 A data, which is just on the resolution edge of what might work with direct methods. Atomic positions for 96% of the entire molecule, containing 514 non-H atoms including three Ca(2+) ions, were easily interpreted from a Fourier map based on the 'Shake-and-Bake' minimal function and CROQUE phase-refinement program. Only six atoms, primarily in the sugar linkage, were missing in this Fourier map. At present, the R factor of the model is 0.143 (R(free) = 0.186) for the 562 non-H atom sites located. The conformation of the RNA/DNA helix is A-form, with a typical A-helix minor-groove width. This paper presents the methodology used in solving this structure. Direct-methods determination of an RNA/DNA hybrid decamer at 1.15 A resolution.,Han GW Acta Crystallogr D Biol Crystallogr. 2001 Feb;57(Pt 2):213-8. PMID:11173466[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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