G-DNA: a twice-folded DNA structure adopted by single-stranded oligo(dG) and its implications for telomeres.
AUTOR(ES)
Panyutin, I G
RESUMO
Our dimethyl sulfate modification experiments suggest that (dG)n stretches within single-stranded DNA fragments, which represent the simplest model for telomeric sequences, adopt a complex intrastrand structure other than a simple hairpin. We present a molecular model for the DNA structure that conforms to dimethyl sulfate methylation data. The principal element of this G-DNA structure is a quadruple helix formed by pairwise antiparallel segments of the twice-folded (dG)n stretch. This quadruple core has two wide and two narrow grooves connected by three loop-shaped segments. The strong stacking interactions of the neighboring guanine tetrads and the large number of hydrogen bonds formed can be the primary reasons that such structures are favored over a common hairpin for long (dG)n stretches. Such compact structures may be formed from (dG)n stretches of telomeric sequences.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=53369Documentos Relacionados
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