Biosynthesis of nucleoside analogues via thermostable nucleoside phosphorylase

Biocatalyzed synthesis of nucleoside analogues was carried out using two thermostable nucleoside phosphorylases from the hyperthermophilic aerobic crenarchaeon Aeropyrum pernix K1. The synthesis of the 2,6-diaminopurine nucleoside and 5-methyluridine was used as a reaction model to test the process. Both the purine nucleoside phosphorylase (apPNP) and uridine phosphorylase (apUP) were functionally expressed in Escherichia coli. The recombinant enzymes were characterized after purification, and both enzymes showed high thermostability and broad substrate specificity. Both enzymes retained 100 % of their activity after 60 min at high temperature, and the optimum temperature for the enzymes was 90–100 °C. The nucleoside phosphorylases obtained from A. pernix are valuable industrial biocatalysts for high-temperature reactions that produce nucleoside drugs in high yields.