A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes.
A hemocyanin-derived antimicrobial peptide from the penaeid shrimp adopts an alpha-helical structure that specifically permeabilizes fungal membranes.
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DOI：
10.1016/j.bbagen.2015.12.010
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发表时间：
2016-03
期刊：
影响因子：
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通讯作者：
V. Petit;J. Rolland;A. Blond;C. Cazevieille;C. Djédiat;J. Péduzzi;C. Goulard;E. Bachère;J. Dupont
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文献类型：
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作者：
V. Petit;J. Rolland;A. Blond;C. Cazevieille;C. Djédiat;J. Péduzzi;C. Goulard;E. Bachère;J. Dupont
背景血蓝蛋白是一种具有多种功能的呼吸蛋白。在多种甲壳动物中，血蓝蛋白可以释放富含组氨酸的抗菌肽以响应微生物的挑战。在对虾中，严格的抗真菌肽是从血蓝蛋白的C-末端释放的。它的作用机制对虾病原体尖孢镰刀菌的影响，使用免疫化学，荧光和透射电子显微镜。ResultsPvHCt折叠成一个两亲性的α-螺旋在膜模拟介质中，并显示在水环境中的随机构象。与F.在尖孢霉中，PvHCt大量结合于真菌菌丝的表面，而不被输入细胞质。在最小抑制浓度下，PvHCt使真菌膜对SYTOX-绿色和4kDa的荧光葡聚糖珠可渗透。较大尺寸的珠粒不能进入细胞质。因此，PvHCt可能对真菌膜造成局部损伤。虽然真菌细胞壁似乎保存，但在真菌孢子和菌丝中观察到细胞质逐渐退化，最常导致细胞溶解。结论PvHCt在真菌菌丝表面的大量积累和随后的插入破坏了其作为渗透屏障的完整性，导致内部稳态的破坏和真菌的死亡。其采用两亲性α-螺旋结构，并选择性地结合并透化真菌细胞。
BackgroundHemocyanins 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.MethodsThe three-dimensional structure of the antifungal peptide PvHCt fromLitopenaeus vannameiwas determined by NMR. Its mechanism of action against the shrimp pathogenFusarium oxysporumwas investigated using immunochemistry, fluorescence and transmission electron microscopy.ResultsPvHCt folded into an amphipathic α-helix in membrane-mimicking media and displayed a random conformation in aqueous environment. In contact withF. 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 the formation of daughter hyphae.ConclusionThe 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 significanceThe 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.