The ability of magnesium(II) and nickel(II) to induce dramatic conformational changes in the synthetic RNA poly(rA)poly(rU) has been investigated. Kinetic experiments, spectrofluorometric titrations, melting experiments and DSC measurements contribute in shedding light on a complex behaviour where the action of metal ions (Na+, Mg2+, Ni2+), in synergism with other operators as the intercalating dye coralyne and temperature, all concur in stabilising a peculiar RNA form. Mg2+ and Ni2+ (M) bind rapidly and almost quantitatively to the duplex (AU) to give a RNA/metal ion complex (AUM). Then, by the union of two AUM units, an unstable tetraaggregate (UAUA(M2)*) is formed which, in the presence of a relatively modest excess of metal, evolves to the UAUM triplex by releasing a single AM strand. On the other hand, under conditions of high metal content, the UAUA(M2)* intermediate rearranges to give a more stable tetra-aggregate (UAUA(M2)). As concerns the role of coralyne (D), it is found that D strongly interacts with UAUA(M2). Also, in the presence of coralyne, the ability of divalent ions to promote the transition of AUD into UAUD is enhanced, according to the efficiency sequence [Ni2+]≫[Mg2+]≫[Na+].

Mg(II) and Ni(II) induce aggregation of poly(rA)poly(rU) to either tetra-aggregate or triplex depending on the metal ion concentration

BIVER, TARITA;
2015

Abstract

The ability of magnesium(II) and nickel(II) to induce dramatic conformational changes in the synthetic RNA poly(rA)poly(rU) has been investigated. Kinetic experiments, spectrofluorometric titrations, melting experiments and DSC measurements contribute in shedding light on a complex behaviour where the action of metal ions (Na+, Mg2+, Ni2+), in synergism with other operators as the intercalating dye coralyne and temperature, all concur in stabilising a peculiar RNA form. Mg2+ and Ni2+ (M) bind rapidly and almost quantitatively to the duplex (AU) to give a RNA/metal ion complex (AUM). Then, by the union of two AUM units, an unstable tetraaggregate (UAUA(M2)*) is formed which, in the presence of a relatively modest excess of metal, evolves to the UAUM triplex by releasing a single AM strand. On the other hand, under conditions of high metal content, the UAUA(M2)* intermediate rearranges to give a more stable tetra-aggregate (UAUA(M2)). As concerns the role of coralyne (D), it is found that D strongly interacts with UAUA(M2). Also, in the presence of coralyne, the ability of divalent ions to promote the transition of AUD into UAUD is enhanced, according to the efficiency sequence [Ni2+]≫[Mg2+]≫[Na+].
Biver, Tarita; Busto, Natalia; Garcia, Begona; Leal, Jose M.; Menichetti, Luisa; Secco, Fernando; Venturini, Marcella
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11568/758412
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 5
social impact