Characterization of the DNA triplex formed by d(TGGGTGGGTGGTTGGGTGGG) and a critical R.Y sequence located in the promoter of the murine Ki-ras proto-oncogene.
FEBS Lett
; 370(1-2): 153-7, 1995 Aug 14.
Article
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| MEDLINE
| ID: mdl-7649296
ABSTRACT
The binding of the G-rich oligonucleotide d(TGGGTGGGTGGTTGGGTGGG) to a critical homopurine-homopyrimidine sequence located in the promoter of the murine Ki-ras proto-oncogene has been investigated. The duplex and the oligonucleotide form a triple helix as evidenced by band-shift electrophoresis, hydroxyapatite (HA) chromatography, UV-melting and circular dichroism (CD) experiments. Upon thermal denaturation in 50 mM Tris-acetate, pH 7.4, 50 mM NaCl, 10 mM MgCl2, 0.1 mM spermine the triplex exhibits two cooperative transitions one of these is attributed to the triplex-to-duplex transformation, the other to the duplex-to-coil transformation. The thermodynamic parameters of triplex formation have been determined by a van't Hoff analysis of the UV-melting curves which provided values of delta H = 79 +/- 8 kcal/mol, delta S = 224 +/- 22 e.u., delta G298 = 12.2 +/- 1.2 kcal/mol. These data are compared with those reported for the YRY triplex motif.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oligodesoxirribonucleótidos
/
ADN
/
Genes ras
/
Regiones Promotoras Genéticas
/
Conformación de Ácido Nucleico
Límite:
Animals
Idioma:
En
Revista:
FEBS Lett
Año:
1995
Tipo del documento:
Article
País de afiliación:
Italia