Metchnikowin Explained

Symbol:	Metchnikowin, Mtk
Metchnikowin
Interpro:	IPR012513

Metchnikowin is a 26-residue antimicrobial peptide of the fruit fly Drosophila melanogaster that displays both antibacterial and antifungal properties.^[1] This peptide is expressed strongly in the Drosophila fat body (an organ similar to the human liver), but is also expressed at surface epithelia in the trachea and gut. This is regulated by the NF-κB signalling pathways Toll and Imd.^[2] Metchnikowin is named after Russian immunologist Élie Metchnikoff, one of the founders of modern immunology.

Structure and function

Metchnikowin has microbicidal activity against the gram-negative bacterium Escherichia coli and filamentous fungus Neurospora crassa at nanomolar concentrations.^[1] It is also one of the most abundant defence peptides in D. melanogaster following infection by the entomopathogenic fungus Beauveria bassiana.^[3] Proline-rich peptides such as metchnikowin can bind to microbe ribosomes, preventing protein translation.^[4]

Notes and References

1. Levashina EA, Ohresser S, Bulet P, Reichhart JM, Hetru C, Hoffmann JA . Metchnikowin, a novel immune-inducible proline-rich peptide from Drosophila with antibacterial and antifungal properties . European Journal of Biochemistry . 233 . 2 . 694–700 . October 1995 . 7588819 . 10.1111/j.1432-1033.1995.694_2.x . free .
2. Levashina EA, Ohresser S, Lemaitre B, Imler JL . Two distinct pathways can control expression of the gene encoding the Drosophila antimicrobial peptide metchnikowin . Journal of Molecular Biology . 278 . 3 . 515–27 . May 1998 . 9600835 . 10.1006/jmbi.1998.1705 .
3. Lemaitre B, Reichhart JM, Hoffmann JA . Drosophila host defense: differential induction of antimicrobial peptide genes after infection by various classes of microorganisms . Proceedings of the National Academy of Sciences of the United States of America . 94 . 26 . 14614–9 . December 1997 . 9405661 . 25070 . 10.1073/pnas.94.26.14614 . 1997PNAS...9414614L . free .
4. Florin T, Maracci C, Graf M, Karki P, Klepacki D, Berninghausen O, Beckmann R, Vázquez-Laslop N, Wilson DN, Rodnina MV, Mankin AS . An antimicrobial peptide that inhibits translation by trapping release factors on the ribosome . Nature Structural & Molecular Biology . 24 . 9 . 752–757 . September 2017 . 28741611 . 5589491 . 10.1038/nsmb.3439 .