New aspects of the interaction of the antibiotic coralyne with RNA: coralyne induces triple helix formation in poly(rA)*poly(rU).
Nucleic Acids Res
; 38(5): 1697-710, 2010 Mar.
Article
em En
| MEDLINE
| ID: mdl-20008509
ABSTRACT
The interaction of coralyne with poly(A)*poly(U), poly(A)*2poly(U), poly(A) and poly(A)*poly(A) is analysed using spectrophotometric, spectrofluorometric, circular dichroism (CD), viscometric, stopped-flow and temperature-jump techniques. It is shown for the first time that coralyne induces disproportionation of poly(A)*poly(U) to triplex poly(A)*2poly(U) and single-stranded poly(A) under suitable values of the [dye]/[polymer] ratio (C(D)/C(P)). Kinetic, CD and spectrofluorometric experiments reveal that this process requires that coralyne (D) binds to duplex. The resulting complex (AUD) reacts with free duplex giving triplex (UAUD) and free poly(A); moreover, ligand exchange between duplex and triplex occurs. A reaction mechanism is proposed and the reaction parameters are evaluated. For C(D)/C(P)> 0.8 poly(A)*poly(U) does not disproportionate at 25 degrees C and dye intercalation into AU to give AUD is the only observed process. Melting experiments as well show that coralyne induces the duplex disproportionation. Effects of temperature, ionic strength and ethanol content are investigated. One concludes that triplex formation requires coralyne be only partially intercalated into AUD. Under suitable concentration conditions, this feature favours the interaction of free AU with AUD to give the AUDAU intermediate which evolves into triplex UAUD and single-stranded poly(A). Duplex poly(A)*poly(A) undergoes aggregation as well, but only at much higher polymer concentrations compared to poly(A)*poly(U).
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Alcaloides de Berberina
/
Poli A-U
/
Antibacterianos
Idioma:
En
Revista:
Nucleic Acids Res
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Itália