RESUMO
RNase L is activated by 2',5'-oligoadenylates (2-5A) at subnanomolar levels to cleave single-stranded RNA. We previously reported the hypothesis that the introduction of an 8-methyladenosine residue at the 2'-terminus of the 2-5A tetramer shifts the 2-5A binding site of RNase L. In this study, we synthesized various 5'-modified 2-5A analogs with 8-methyladenosine at the 2'-terminus. The doxifluridine-conjugated 8-methyladenosine-substituted 2-5A analog was significantly more effective as an activator of RNase L than the parent 5'-monophophorylated 2-5A tetramer and showed a tumor suppressive effect against human cervical cancer cells.
Assuntos
Antineoplásicos/farmacologia , Endorribonucleases/metabolismo , Floxuridina/farmacologia , Antineoplásicos/química , Espectroscopia de Ressonância Magnética Nuclear de Carbono-13 , Ativação Enzimática , Feminino , Floxuridina/química , Células HeLa , Humanos , Espectrometria de Massas , Espectroscopia de Prótons por Ressonância MagnéticaRESUMO
Human ribonuclease L (RNase L), an interferon-induced endoribonuclease, becomes enzymatically active after binding to 2-5A. The 5'-phosphoryl group of 2-5A is reportedly necessary for the conformational change leading to RNase L activation. However, we found that 5'-O-dephosphorylated 2-5A tetramer analogs with 8-methyladenosine at the 2'-terminus were more effective as an activator of RNase L than the parent 2-5A tetramer. Introduction of 8-methyladenosine is thought to induce a dramatic shift of 2-5A in the binding site of RNase L.
Assuntos
Nucleotídeos de Adenina/química , Adenosina/análogos & derivados , Endorribonucleases/metabolismo , Oligorribonucleotídeos/química , Nucleotídeos de Adenina/metabolismo , Nucleotídeos de Adenina/farmacologia , Adenosina/química , Adenosina/metabolismo , Adenosina/farmacologia , Animais , Cristalografia por Raios X , Ativação Enzimática/efeitos dos fármacos , Humanos , Oligorribonucleotídeos/metabolismo , Oligorribonucleotídeos/farmacologia , Fosforilação , Proteínas Recombinantes/metabolismo , Venenos de SerpentesRESUMO
The 2',5'-oligoadenylate (2-5A) system is an interferon (IFN)-regulated RNA decay pathway that provides innate immunity against viral infections. The biological action of the 2-5A system is mediated by RNase L, an endoribonuclease that becomes enzymatically active after binding to 2-5A. It has been reported that the 5'-phosphoryl group of 2-5A is required for RNase L activation. However, we have found that 5'-O-dephosphorylated 2-5A tetramer analogs with 8-methyladenosine at the 2'-terminus were more effective as an activator of RNase L than the parent 2-5A (p5'A2'p5'A2'p5'A2'p5'A2'). Introduction of 8-methyladenosine is thought to induce a dramatic shift in the binding site of RNase L.