Structure and stability of X.G.C mismatches in the third strand of intramolecular triplexes
1991; American Association for the Advancement of Science; Volume: 254; Issue: 5029 Linguagem: Inglês
10.1126/science.254.5029.270
ISSN1095-9203
AutoresRF Macaya, DE Gilbert, Shiva Malek, JS Sinsheimer, Juli Feigon,
Tópico(s)RNA and protein synthesis mechanisms
ResumoIntramolecular DNA triplexes that contain eight base triplets formed from the folding of a single DNA strand tolerate a single X.G.C mismatch in the third strand at acidic pH. The structure and relative stability of all four triplets that are possible involving a G.C Watson-Crick base pair were determined with one- and two-dimensional proton nuclear magnetic resonance techniques. Triplexes containing A.G.C, G.G.C, or T.G.C triplets were less stable than the corresponding parent molecule containing a C.G.C triplet. However, all mismatched bases formed specific hydrogen bonds in the major groove of the double helix. The relative effect of these mismatches on the stability of the triplex differs from the effect assayed (under different conditions) by two-dimensional gel electrophoresis and DNA cleavage with oligonucleotide EDTA.Fe(II).
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