Creation of strain – producer of bacterial purine nucleoside phosphorylase fused with human annexin A5

Abstract

It is known that bacterial purine nucleoside phosphorylase (PNPase), unlike mammalian PNPase, is capable of phosphorolytic cleavage of adenosine and its derivatives to form free nitrogen bases. This makes it possible to use bacterial PNPase (provided the problem of delivering this enzyme or its gene to target cells is solved) as a prodrug therapy for cancer. In addition, PNPase in a tumor bed can destroy extracellular adenosine, which is known to protect cancer cells from antitumor immunity.As a result of the study, a new strain of Escherichia coli was constructed, producing a chimeric protein whose molecule consists of a homologous PNPase fused to human annexin A5, a protein showing affinity for cancer cells.The production capacity of the producer strain of the chimeric protein “Annexin-PNPase” with respect to PNPase calculated from the results of the inosine phosphorolysis reaction, was 10,200 units/ml of culture liquid. The obtained strain is intended for creation of a technology for obtaining new antitumor preparations.