Enterocin and its derivatives are bacteriocins synthesized by the lactic acid bacteria, '' Enterococcus''. This class of polyketide

antibiotic An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

s are effective against foodborne pathogens including ''

L. monocytogenes ''Listeria monocytogenes'' is the species of pathogenic bacteria that causes the infection listeriosis. It is a Facultative anaerobic organism, facultative anaerobic bacterium, capable of surviving in the presence or absence of oxygen. It can gro ...

, Listeria,'' and '' Bacillus.'' Due to its proteolytic degradability in the

gastrointestinal tract The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organ (biology), organs of the digestive syste ...

, enterocin is used for controlling foodborne pathogens via human consumption.

History

Enterocin was discovered from soil and marine ''

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, ...

'' strains as well as from marine ascidians of ''

Didemnum ''Didemnum'' is a genus of colonial tunicates in the family Didemnidae. It is the most speciose genus in the didemnid family. Species in this genus often have small calcareous spicules embedded in the tunic and form irregular or lobed colonies. S ...

'' and it has also been found in a mangrove strains ''

Streptomyces qinglanensis ''Streptomyces qinglanensis'' is a bacterium species from the genus of ''Streptomyces'' which has been isolated from mangrove soil from Wenchang in the Hainan in China.Deutsche Sammlung von Mikroorganismen und Zellkulturenbr>/ref> See also * ...

'' and ''

Salinispora pacifica ''Salinispora pacifica'' is an obligate marine actinomycetes bacterium species in the genus '' Salinispora''. See also * ''Salinispora tropica ''Salinispora tropica'' is an obligate marine actinomycete bacterium species. It produces salino ...

''.

Total synthesis

The total synthesis of enterocin has been reported.

Biosynthesis

Enterocin has a caged, tricyclic,

nonaromatic In chemistry, aromaticity is a chemical property of cyclic (ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satura ...

core and its formation undergoes a flavoenzyme (EncM) catalyzed Favorskii-like rearrangement of a poly(beta-carbonyl). Studies done on enterocin have shown that it is biosynthesized from a type II polyketide synthase (PKS) pathway, starting with a structure derived from

phenylalanine Phenylalanine (symbol Phe or F) is an essential α-amino acid with the formula . It can be viewed as a benzyl group substituted for the methyl group of alanine, or a phenyl group in place of a terminal hydrogen of alanine. This essential amino a ...

or activation of benzoic acid followed by the EncM catalyzed rearrangement. Enterocin biosynthesis

The enzyme EncN catalyzes the

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-dependent transfer of the benzoate to EncC, the acyl carrier protein. EncC transfers the aromatic unit to EncA-EncB, the ketosynthase in order for malonation via FabD, the

malonyl-CoA Malonyl-CoA is a coenzyme A derivative of malonic acid. Functions It plays a key role in chain elongation in fatty acid biosynthesis and polyketide biosynthesis. Fatty acid biosynthesis Malonyl-CoA provides 2-carbon units to fatty acids and commi ...

:ACP transacylase. A Claisen condensation occurs between the benzoyl and malonyl groups and occurs six more times followed by reaction with EncD, a ketoreductase; the intermediate undergoes the EncM catalyzed oxidative rearrangement to form the enterocin tricyclic core. Further reaction with ''O''-methyltransferase, EncK and

cytochrome P450 Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...

hydroxylase, EncR yields enterocin.

References

{{reflist Antibiotics Oxygen heterocycles Lactones Heterocyclic compounds with 3 rings Methoxy compounds