Katanosin

Sources

Katanosins have been isolated from the fermentation broth of microorganisms, such as Cytophaga. or the Gram-negative bacterium Lysobacter sp.

Structure

Katanosins are cyclic depsipeptides (acylcyclodepsipeptides). These non-proteinogenic structures are not ordinary proteins derived from primary metabolism. Rather, they originate from bacterial secondary metabolism. Accordingly, various non-proteinogenic (non-ribosomal) 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 (“lariat structure”). The peptidic ring is closed with an ester bond (lactone).

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 (lysobactin) have been described in 2007.

References

References

1. (1988). "Lysobactin, a novel antibacterial agent produced by Lysobacter sp. II. Biological properties". The Journal of Antibiotics.
2. (1988). "Lysobactin, a novel antibacterial agent produced by Lysobacter sp. I. Taxonomy, isolation and partial characterization". The Journal of Antibiotics.
3. (1988). "Isolation and characterization of katanosins a and B". The Journal of Antibiotics.
4. (2016). "The Mechanism of Action of Lysobactin". Journal of the American Chemical Society.
5. (2007). "Structure and total synthesis of lysobactin (katanosin B)". Angewandte Chemie International Edition in English.
6. (2007). "Total synthesis of lysobactin". Journal of the American Chemical Society.