Nourseothricin (NTC) is a member of the streptothricin-class of

aminoglycoside antibiotics Aminoglycoside is a medicinal and bacteriologic category of traditional Gram-negative antibacterial medications that inhibit protein synthesis and contain as a portion of the molecule an amino-modified glycoside ( sugar). The term can also refer ...

produced by ''

Streptomyces ''Streptomyces'' is the largest genus of Actinomycetota and the type genus of the family Streptomycetaceae. Over 500 species of ''Streptomyces'' bacteria have been described. As with the other Actinomycetota, streptomycetes are gram-positive, ...

'' species. Chemically, NTC is a mixture of the related compounds streptothricin C, D, E, and F. NTC inhibits

protein synthesis Protein biosynthesis (or protein synthesis) is a core biological process, occurring inside cells, balancing the loss of cellular proteins (via degradation or export) through the production of new proteins. Proteins perform a number of critical ...

by inducing miscoding. It is used as a selection marker for a wide range of organisms including

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

yeast Yeasts are eukaryotic, single-celled microorganisms classified as members of the fungus kingdom. The first yeast originated hundreds of millions of years ago, and at least 1,500 species are currently recognized. They are estimated to consti ...

filamentous fungi A mold () or mould () is one of the structures certain fungi can form. The dust-like, colored appearance of molds is due to the formation of spores containing fungal secondary metabolites. The spores are the dispersal units of the fungi. Not ...

, and

plant cell Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae. Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capabi ...

s. It is not known to have adverse side-effects on positively selected cells, a property cardinal to a selection drug. NTC can be inactivated by nourseothricin N-acetyl transferase (NAT) from '' Streptomyces noursei'', an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different molecule ...

that acetylates the beta-amino group of the beta-lysine residue of NTC. NAT can thus act as an

antibiotic resistance Antimicrobial resistance (AMR) occurs when microbes evolve mechanisms that protect them from the effects of antimicrobials. All classes of microbes can evolve resistance. Fungi evolve antifungal resistance. Viruses evolve antiviral resistanc ...

gene.

Properties

NTC is highly soluble in water (~ 1 g/mL) and stable in solution for 2 years at 4 °C.NTC propertiesJena Bioscience
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References

Aminoglycoside antibiotics Eukaryotic selection compounds {{antibiotic-stub