Tritium exchange on transfer RNA: slowly exchanging protons sensitive to a change in the dihydrouridine stem.
Proc Natl Acad Sci U S A
; 78(3): 1567-71, 1981 Mar.
Article
em En
| MEDLINE
| ID: mdl-7015338
ABSTRACT
Measurements of tritium exchange on tRNA were made for periods from 0.5 min to 8 hr after separation from labeled solvent. The exchange curve was analysed in terms of three kinetic classes of exchanging protons with half-lives of 5 hr (12 protons), 0.54 hr (37 protons) and about 3.5 min (58 protons) at 0 degrees C in 0.14 M K+/10 mM Mg2+. The behaviour under varying ionic conditions of protons in the slowest exchange class and of some protons in the intermediate class suggests that they are dependent on the tertiary structure of the molecule. Moreover, in the same range of exchange times characteristic of these latter protons, about 9 more protons were observed in the case of a mutant form of tRNA Trp, the UGA-suppressor species, than in the wild-type tRNATrp. These two species differ only in base 24 in the dihydrouridine stem. This dynamic difference between the wild-type and suppressor species may be related to a functionally important difference in coupling between the conformation of the molecule and interactions at the anticodon.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
3_ND
Base de dados:
MEDLINE
Assunto principal:
Uridina
/
RNA de Transferência
Tipo de estudo:
Diagnostic_studies
/
Prognostic_studies
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
1981
Tipo de documento:
Article