Katanosin


Katanosins are a group of antibiotics. They are natural products with strong antibacterial potency. So far, katanosin A and katanosin B have been described.

Structure

Katanosins are cyclic depsipeptides. These non-proteinogenic structures are not ordinary proteins derived from primary metabolism. Rather, they originate from bacterial secondary metabolism. Accordingly, various non-proteinogenic amino acids are found in katanosins, such as 3-hydroxyleucine, 3-hydroxyasparagine, allothreonine and 3-hydroxyphenylalanine. All katanosins have a cyclic and a linear segment. The peptidic ring is closed with an ester bond.
Katanosin A and B differ in the amino acid position 7. The minor metabolite katanosin A has a valine in this position, whereas the main metabolite katanosin B carries an isoleucine.

Biological activity

Katanosin antibiotics target the bacterial cell wall biosynthesis. They are highly potent against problematic Gram-positive hospital pathogens such as staphylococci and enterococci. Their promising biological activity attracted various biological and chemical research groups. Their in-vitro potency is comparable with the current “last defence” antibiotic vancomycin.

Chemical synthesis

The first total syntheses of katanosin B have been described in 2007.