Copsin is a fungal defensin that acts as an antimicrobial polypeptide secreted from the

inky cap ''Coprinopsis atramentaria'', commonly known as the common ink cap, tippler's bane, or inky cap, is a species of fungus. Previously known as ''Coprinus atramentarius'', it is the second best-known ink cap and previous member of the genus '' ...

mushroom, first reported at the end of 2014. The fungal defensin acts against

gram positive bacteria In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

History

In October 2014, a collaboration of the

Swiss Federal Institute of Technology The Swiss Federal Institutes of Technology are two institutes of higher education in Switzerland (part of the ETH Domain): * Swiss Federal Institute of Technology in Lausanne Swiss most commonly refers to: * the adjectival form of Switzerland *Sw ...

, Switzerland and the

University of Bonn The University of Bonn, officially the Rhenish Friedrich Wilhelm University of Bonn (), is a public research university in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the () on 18 October 1818 by Frederick Willi ...

, Germany reported, that they had identified a new

antimicrobial peptide Antimicrobial peptides (AMPs), also called host defence peptides (HDPs) are part of the innate immune response found among all classes of life. Fundamental differences exist between prokaryotic and eukaryotic cells that may represent targets for ...

, excreted from the

mushroom (''Coprinopsis cinereacopsin'') grown on horse dung.

Biosynthesis

The

polypeptide Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty ...

was recombinantly produced in a yeast named

Pichia pastoris ''Komagataella'' is a methylotrophic yeast within the order Saccharomycetales. It was found in the 1960s as ''Pichia pastoris'', with its feature of using methanol as a source of carbon and energy. In 1995, ''P. pastoris'' was reassigned into t ...

which grew over five days. the peptide has an extremely compact three-dimensional structure on

NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique based on re-orientation of atomic nuclei with non-zero nuclear spins in an external magnetic f ...

Mechanism of action

Copsin is an inhibitor of cell wall synthesis by binding to

Lipid II Lipid II is a precursor molecule in the synthesis of the cell wall of bacteria. It is a peptidoglycan, which is amphipathic and named for its bactoprenol hydrocarbon chain, which acts as a lipid anchor, embedding itself in the bacterial cell me ...

. It was reported to be potent in the petri dish against

Gram positive bacteria In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain is ...

which have a cell wall, including

Enterococcus faecium ''Enterococcus faecium'' is a Gram-positive, gamma-hemolytic or non-hemolytic bacterium in the genus ''Enterococcus''. It can be commensal (innocuous, coexisting organism) in the gastrointestinal tract of humans and animals, but it may also be ...

and

Listeria ''Listeria'' is a genus of bacteria that acts as an intracellular parasite in mammals. As of 2024, 28 species have been identified. The genus is named in honour of the British pioneer of sterile surgery Joseph Lister. ''Listeria'' species ...

monocytogenes. It is not active against bacteria with an outer membrane, such as gram negative bacteria.

Potential use

The "exceptionally stable protein", can be boiled at 100 degrees Celsius, can be mixed in strong acid for hours, and can also survive very aggressive enzymes, " remaining completely active". It is considered for use in the food industry for

food preservation Food preservation includes processes that make food more resistant to microorganism growth and slow the redox, oxidation of fats. This slows down the decomposition and rancidification process. Food preservation may also include processes that in ...

References

{{reflist, 2 Polypeptide antibiotics Defensins

History

Biosynthesis

Mechanism of action

Potential use

See also

References