Comparison of interactions of diamine and Mg²âº with RNA tertiary structures: similar versus differential effects on the stabilities of diverse RNA folds.
Biochemistry
; 52(34): 5911-9, 2013 Aug 27.
Article
em En
| MEDLINE
| ID: mdl-23899366
ABSTRACT
Cations play a large role in stabilizing the native state of RNA in vivo. In addition to Mg²âº, putrescine²âº is an abundant divalent cation in bacterial cells, but its effect on the folding of RNA tertiary structure has not been widely explored. In this study, we look at how the stabilities of four structured RNAs, each with a different degree of dependence on K⺠and Mg²âº, are affected by putrescine²âº relative to Mg²âº. Through the use of thermal melts, we observe that (i) at a given concentration, putrescine²âº is less effective than Mg²âº at stabilizing RNA, (ii) the stability imparted to RNA by various diamines is a function of charge density (average separation distance between charges) as well as the flexibility of the counterion, and (iii) when Mg²âº is already present in a buffer, further addition of putrescine²âº may either destabilize or stabilize RNA structure, depending on whether the native RNA does or does not chelate Mg²âº ion, respectively. At ion concentrations likely to be found in vivo, the effect of putrescine²âº on the free energy of folding of an RNA tertiary structure is probably quite small compared to that of Mg²âº, but the ability of mixed Mg²âº/putrescine²âº environments to (in effect) discriminate between different RNA architectures suggests that, in some cells, the evolution of functional RNA structures may have been influenced by the presence of putrescine²âº.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
RNA
/
Putrescina
/
Estabilidade de RNA
/
Dobramento de RNA
/
Magnésio
Idioma:
En
Ano de publicação:
2013
Tipo de documento:
Article