Antisense RNA control of gene expression in bacteriophage P22. II. Kinetic mechanism and cation specificity of the pairing reaction.
RNA
; 3(2): 157-74, 1997 Feb.
Article
em En
| MEDLINE
| ID: mdl-9042943
ABSTRACT
The bacteriophage P22 sar RNA-ant mRNA pairing reaction was characterized kinetically. The pairing reaction proceeds by a three-step pathway. First, reversible base pairs form between complementary hairpin loops in sar RNA and ant RNA (Kd = 270 nM). Next, stable duplex formation initiates between single-stranded nucleotides in sar RNA and ant RNA; the ant RNA nucleotides are at the bottom of a hairpin stem that is partially accessible. Concomitant unwinding of one sar RNA hairpin and the complementary ant RNA hairpin then occurs, to form a partially paired intermediate (k2 = 12 min(-1). Finally, a complete duplex forms after unwinding of the other sar RNA hairpin and the complementary ant RNA hairpin (k3 = 7 min(-1). Experiments with sar RNA sequence and length variants demonstrate that the precise structures of both sar RNA hairpins affect the kinetic parameters. The pairing reaction is Mg2+-dependent, and shows high specificity for the required cation. Maximal pairing rates are achieved when more than one Mg2+ ion is bound. The cation-dependence and specificity indicate a requirement for Mg2+-dependent tertiary structure.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Regulação Viral da Expressão Gênica
/
RNA Antissenso
/
Bacteriófago P22
Idioma:
En
Revista:
RNA
Assunto da revista:
BIOLOGIA MOLECULAR
Ano de publicação:
1997
Tipo de documento:
Article
País de afiliação:
Estados Unidos