RESUMEN
Our studies have led to the identification of an E. coli PNP mutant (M64V) that is able to cleave numerous 5'-modified nucleoside analogs with much greater efficiency than the wild-type enzyme. The biological activity of the three best substrates of this mutant (9-[6-deoxy-alpha-L-talofuranosyl]-6-methylpurine (methyl(talo)-MeP-R), 9-[6-deoxy-alpha-L-talofuranosyl]-2-F-adenine, and 9-[alpha-L-lyxofuranosyl]-2-F-adenine) were evaluated so that we can optimally utilize these compounds. Our results indicated that the mechanism of toxicity of methyl(talo)-MeP-R to mice was due to its cleavage to MeP by a bacterial enzyme, and that the toxicity of the two F-Ade analogs was due to their cleavage to F-Ade by mammalian methylthioadenosine phosphorylase.
Asunto(s)
Escherichia coli/enzimología , Mutación , Nucleósidos/síntesis química , Nucleósidos/farmacología , Profármacos/farmacología , Purina-Nucleósido Fosforilasa/genética , Purina-Nucleósido Fosforilasa/metabolismo , Animales , Línea Celular , Línea Celular Tumoral , Química Farmacéutica/métodos , Diseño de Fármacos , Escherichia coli/genética , Humanos , Concentración 50 Inhibidora , Ratones , Modelos Químicos , Nucleósidos/química , Profármacos/síntesis química , Especificidad por Sustrato , Tionucleósidos/químicaRESUMEN
A novel series of 6-methylpurine nucleoside derivatives with substitutions at 5-position have been synthesised These compounds bear a 5'-heterocycle such as triazole or a imidazole with a two carbon chain, and an ether, thio ether or amine. To extend the SAR study of 2-fluoroadenine and 6-methyl purine nucleosides, their corresponding alpha-linker nucleosides with L-xylose and L-lyxose were also synthesized. All of these compounds have been evaluated for their substrate activity with E. coli PNP.