Metal ion complexes of macrocyclic polyamines enhance both the phosphate hydrolysis and imidazole ring opening of RNA 5'-cap structure.
Chem Biodivers
; 2(1): 92-103, 2005 Jan.
Article
em En
| MEDLINE
| ID: mdl-17191922
ABSTRACT
The cleavage of P1-(7-methylguanosyl-5') P3-(guanosyl-5') triphosphate, a RNA 5'-cap model, by 2-hydroxyethyl- (6a-6c) and 2-aminoethyl- (7a-7c) substituted macrocycles in the presence and absence of Zn2+ and Cu2+ ions has been studied at pH 7.2 and 60 degrees. In the presence of the metal ions, hydrolysis of the phosphate group is enhanced. The mono- and dinuclear Zn2+ complexes promote solely the phosphate hydrolysis, whereas the corresponding Cu2+ complexes accelerate both the phosphate hydrolysis and the imidazole ring opening of the 7-methylguanine base. In the absence of the metal ions, the macrocycles mainly promote breakdown of the 7-methylguanine base, most probably by enhancing the nucleophilic attack of hydroxide ion on the C(8)-atom by shielding the repulsive negative charge on the phosphate moiety. The 2-hydroxyethyl and 2-aminoethyl side arms exhibit a two- to three-fold rate acceleration. Opening of the imidazole ring eventually results in cleavage of the triphosphate bridge.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfatos
/
Poliaminas
/
Zinco
/
Capuzes de RNA
/
Cobre
/
Compostos Macrocíclicos
Idioma:
En
Ano de publicação:
2005
Tipo de documento:
Article