Blasticidin S is a peptidyl nucleoside antibiotic isolated from Streptomyces griseochromogenes. It is a potent inhibitor of protein synthesis in bacteria and eukaryotes, while also active in fungi, nematodes, and tumor cells. Blasticidin S acts by blocking hydrolysis of peptidyl-tRNA induced by release factors and inhibits peptide bond formation. It is used as a selection agent in both mammalian and bacterial cells. The recommended working concentration ranges from 1 to 30 µg/mL depending on the cell line and 25–100 µg/mL for bacterial selection. Cell death occurs rapidly, and blasticidin-resistant stable mammalian cell lines can be generated in less than one week.

Resistance to blasticidin S is conferred by BSR and BSD, isolated from Bacillus cereus K55-S and Aspergillus terreus respectively. The BSR resistance gene encodes blasticidin S deaminase, which catalyzes the conversion of blasticidin S to deaminohydroxyblasticidin S. Deaminohydroxyblasticidin S is a biologically inactive derivative of blasticidin S and does not interact with or inhibit prokaryotic or eukaryotic ribosomes. The BSD resistance gene also encodes a blasticidin S deaminase, which catalyzes a similar reaction to the BSR deaminase.

For bacterial selection purposes, the salt content of the LB medium must remain low (<90 mM) and the pH should not exceed 7.0 to maintain the activity of basticidin S. A kill curve is recommended in order to determine the minimum effective blasticidin S concentration to kill non-resistant cells.

Applications
View detailed protocols on blasticidin selection in mammalian cells, E. coli, and yeast.