Conformational variability of recombination R-triplex formed by the mammalian telomeric sequence.
J Biomol Struct Dyn
; 34(6): 1298-306, 2016 Jun.
Article
em En
| MEDLINE
| ID: mdl-26308235
ABSTRACT
Alignment of three nucleic acids strands, in which the third strand is identical to one of the DNA duplex strands, occurs in various cellular systems. In the case of telomeric t-loops, recognition between the DNA duplex and the homologous single strand is likely to be mediated by proteins through formation of the transient recombination-type R-triplex. Earlier, using 2-aminopurine as a fluorescent reporting base, we evaluated the thermodynamic characteristics of intramolecular R-triplex formed by a mixed nucleotide sequence. Here, we used this approach to explore a propensity of the telomeric TTAGGG repeat to form the R-triplex. The circular dichroism spectral changes detected upon formation of the R-triplex suggest that this process is accompanied by specific conformational changes in DNA, including a local destabilization of the target duplex next to a GGG run revealed by the fluorescence of the reporting 2-aminopurine base. Surprisingly, stability of the R-triplex formed by telomeric sequence depends strikingly on the counter ion, being higher for Na(+) than for Li(+). Taken together these findings indicate a significant conformational variability of telomeric DNA in the context of recombination-type R-triplex, a phenomenon of possible biological relevance.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA
/
Modelos Moleculares
/
Telômero
/
Conformação de Ácido Nucleico
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
J Biomol Struct Dyn
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Federação Russa