A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes

Type Article
Date 2016-03
Language English
Author(s) Petit Vanessa W.1, 5, Rolland Jean-Luc2, Blond Alain1, Cazevieille Chantal4, Djediat Chakib1, Peduzzi Jean1, Goulard Christophe1, Bachere Evelyne2, Dupont Joelle3, Destoumieux-Garzon Delphine6, Rebuffat Sylvie1
Affiliation(s) 1 : Univ Paris 04, CNRS, MNHN, Lab Mol Commun & Adaptat Microorganismes MCAM,UMR, CP 54,57 Rue Cuvier, F-75005 Paris, France.
2 : Univ Montpellier, IHPE, IFREMER, CNRS,UPVD,UMR 5244, F-34090 Montpellier, France.
3 : Univ Paris 04, CNRS, Univ Paris 06,MNHN, Inst Systemat Evolut Biodiversite ISYEB,UMR 7205, F-75005 Paris, France.
4 : COMET, Plateau Microscopie Elect, Plateforme Montpellier RIO Imaging, F-34091 Montpellier, France.
5 : CEA, Inst Rech Radiobiol Cellulaire & Mol IRCM, Lab Rech Reparat & Transcript Cellules Souches LR, F-92265 Fontenay Aux Roses, France.
6 : Univ Montpellier, IHPE, IFREMER, CNRS,UPVD,UMR 5244, F-34090 Montpellier, France.
Source Biochimica Et Biophysica Acta-general Subjects (0304-4165) (Elsevier Science Bv), 2016-03 , Vol. 1860 , N. 3 , P. 557-568
DOI 10.1016/j.bbagen.2015.12.010
WOS© Times Cited 27
Keyword(s) Antimicrobial peptide, Amphipathic helix, Fungi, Membrane bilayer, Nuclear magnetic resonance (NMR), Fluorescence microscopy
Abstract Background. Hemocyanins are respiratory proteins with multiple functions. In diverse crustaceans hemocyanins can release histidine-rich antimicrobial peptides in response to microbial challenge. In penaeid shrimp, strictly antifungal peptides are released from the C-terminus of hemocyanins.

Methods. The three-dimensional structure of the antifungal peptide PvHCt from Litopenaeus vannamei was determined by NMR. Its mechanism of action against the shrimp pathogen Fusarium oxysporum was investigated using immunochemistry, fluorescence and transmission electron microscopy.

Results. PvHCt folded into an amphipathic α-helix in membrane-mimicking media and displayed a random conformation in aqueous environment. In contact with F. oxysporum, PvHCt bound massively to the surface of fungal hyphae without being imported into the cytoplasm. At minimal inhibitory concentrations, PvHCt made the fungal membrane permeable to SYTOX-green and fluorescent dextran beads of 4 kDa. Higher size beads could not enter the cytoplasm. Therefore, PvHCt likely creates local damages to the fungal membrane. While the fungal cell wall appeared preserved, gradual degeneration of the cytoplasm most often resulting in cell lysis was observed in fungal spores and hyphae. In the remaining fungal cells, PvHCt induced a protective response by formation of daughter hyphae.

Conclusion. The massive accumulation of PvHCt at the surface of fungal hyphae and subsequent insertion into the plasma membrane disrupt its integrity as a permeability barrier, leading to disruption of internal homeostasis and fungal death.

General significance. The histidine-rich antimicrobial peptide PvHCt derived from shrimp hemocyanin is a strictly antifungal peptide, which adopts an amphipathic α-helical structure, and selectively binds to and permeabilizes fungal cells.
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Petit Vanessa W., Rolland Jean-Luc, Blond Alain, Cazevieille Chantal, Djediat Chakib, Peduzzi Jean, Goulard Christophe, Bachere Evelyne, Dupont Joelle, Destoumieux-Garzon Delphine, Rebuffat Sylvie (2016). A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes. Biochimica Et Biophysica Acta-general Subjects, 1860(3), 557-568. Publisher's official version : https://doi.org/10.1016/j.bbagen.2015.12.010 , Open Access version : https://archimer.ifremer.fr/doc/00301/41202/