G418 (Geneticin) is an aminoglycoside antibiotic similar in structure to gentamicin B1. It is produced by Micromonospora rhodorangea. G418 blocks polypeptide synthesis by inhibiting the elongation step in both prokaryotic and eukaryotic cells.

[1] Holbrook Selina Y. L., Gentry Matthew S., Tsodikov Oleg V., Garneau-Tsodikova Sylvie. Nucleoside triphosphate cosubstrates control the substrate profile and efficiency of aminoglycoside 3′-O-phosphotransferase type IIa, MedChemComm, 2018