Neomycin phosphotransferase II (NPTII) (NPTII)

Neomycin phosphotransferase II (NPTII) is a bacterial enzyme originally derived from the transposon Tn5 of Escherichia coli that functions as an aminoglycoside-modifying enzyme [1, 4]. It catalyzes the ATP-dependent phosphorylation of the 3'-hydroxyl group of various aminoglycoside antibiotics, such as neomycin, kanamycin, and paromomycin, as well as the eukaryotic selection agent G418 (Geneticin) [5, 12]. This modification prevents the antibiotics from binding to their primary target, the 30S ribosomal subunit, thereby neutralizing their ability to inhibit bacterial protein synthesis [13, 17]. Beyond its clinical relevance in antibiotic resistance, NPTII is extensively utilized as a selectable marker in plant and animal biotechnology to identify cells that have successfully integrated foreign DNA [3, 8, 14]. Regulatory safety assessments for its use in genetically modified crops have demonstrated that the protein is rapidly degraded under simulated mammalian digestive conditions and poses minimal risk to human health [2, 9, 15].

Other names

Aminoglycoside 3'-phosphotransferase type IIAPH(3')-IIAPH(3')IIaKanamycin kinase type IINeomycin-kanamycin phosphotransferase type IInptIIneokan

Inactivates aminoglycoside antibiotics by catalyzing the transfer of a phosphate group from ATP to the 3'-hydroxyl position of the drug, which sterically hinders its binding to the bacterial 30S ribosomal subunit [5, 13, 14].