Departamento de Química e Bioquímica, Faculdade de Ciências, Centro Investigação em Química CIQ(UP), Universidade do Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
Amino Acids. 2012 Dec;43(6):2265-77. doi: 10.1007/s00726-012-1304-0. Epub 2012 Apr 29.
Two antimicrobial cryptopeptides from the N1 domain of bovine lactoferrin, lactoferricin (LFcin17-30) and lactoferrampin (LFampin265-284), together with a hybrid version (LFchimera), were tested against the protozoan parasite Leishmania. All peptides were leishmanicidal against Leishmania donovani promastigotes, and LFchimera showed a significantly higher activity over its two composing moieties. Besides, it was the only peptide active on Leishmania pifanoi axenic amastigotes, already showing activity below 10 μM. To investigate their leishmanicidal mechanism, promastigote membrane permeabilization was assessed by decrease of free ATP levels in living parasites, entrance of the vital dye SYTOX Green (MW = 600 Da) and confocal and transmission electron microscopy. The peptides induced plasma membrane permeabilization and bioenergetic collapse of the parasites. To further clarify the structural traits underlying the increased leishmanicidal activity of LFchimera, the activity of several analogues was assessed. Results revealed that the high activity of these hybrid peptides seems to be related to the order and sequence orientation of the two cryptopeptide moieties, rather than to their particular linkage through an additional lysine, as in the initial LFchimera. The incorporation of both antimicrobial cryptopeptide motifs into a single linear sequence facilitates chemical synthesis and should help in the potential clinical application of these optimized analogues.
两种来自牛乳铁蛋白 N1 结构域的抗菌隐肽，乳铁蛋白素（LFcin17-30）和乳铁蛋白肽（LFampin265-284），以及一种杂交版本（LFchimera），都被测试了对原生动物寄生虫利什曼原虫的作用。所有这些肽都对利什曼原虫无鞭毛体具有杀利什曼原虫活性，而 LFchimera 与其两个组成部分相比表现出更高的活性。此外，它是唯一对利什曼原虫 pifanoi 无鞭毛体有活性的肽，其活性已低于 10μM。为了研究它们的杀利什曼原虫机制，通过活寄生虫中游离 ATP 水平的降低、生命染料 SYTOX Green（MW=600Da）的进入以及共聚焦和透射电子显微镜评估了无鞭毛体膜的通透性。这些肽诱导了质膜通透性和寄生虫的生物能量崩溃。为了进一步阐明 LFchimera 增强杀利什曼原虫活性的结构特征，评估了几种类似物的活性。结果表明，这些杂交肽的高活性似乎与两个隐肽结构域的顺序和序列取向有关，而不是它们通过额外的赖氨酸的特定连接，就像最初的 LFchimera 那样。将两种抗菌隐肽基序纳入单个线性序列中有助于化学合成，并且应该有助于这些优化类似物的潜在临床应用。
