Transient Hoogsteen base pairs in canonical duplex DNA.
Nature
; 470(7335): 498-502, 2011 Feb 24.
Article
em En
| MEDLINE
| ID: mdl-21270796
ABSTRACT
Sequence-directed variations in the canonical DNA double helix structure that retain Watson-Crick base-pairing have important roles in DNA recognition, topology and nucleosome positioning. By using nuclear magnetic resonance relaxation dispersion spectroscopy in concert with steered molecular dynamics simulations, we have observed transient sequence-specific excursions away from Watson-Crick base-pairing at CA and TA steps inside canonical duplex DNA towards low-populated and short-lived Aâ¢T and Gâ¢C Hoogsteen base pairs. The observation of Hoogsteen base pairs in DNA duplexes specifically bound to transcription factors and in damaged DNA sites implies that the DNA double helix intrinsically codes for excited state Hoogsteen base pairs as a means of expanding its structural complexity beyond that which can be achieved based on Watson-Crick base-pairing. The methods presented here provide a new route for characterizing transient low-populated nucleic acid structures, which we predict will be abundant in the genome and constitute a second transient layer of the genetic code.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
DNA
/
Pareamento de Bases
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article