Structure-Activity Relationship of Synthetic Variants of the Milk-Derived Antimicrobial Peptide αs2-Casein f(183-207)
Structure-Activity Relationship of Synthetic Variants of the Milk-Derived Antimicrobial Peptide αs2-Casein f(183-207)
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DOI：
10.1128/aem.01394-13
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发表时间：
2013-09-01
影响因子：
4.4
通讯作者：
Hill, Colin
中科院分区：
文献类型：
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作者：
Alvarez-Ordonez, Avelino;Begley, Maire;Hill, Colin
基于模板的抗菌肽（AMP）衍生物的研究，通过操作的氨基酸序列是有帮助的，以确定性质或残基的生物活性是重要的。本研究揭示了乳源性α（s2）-酪蛋白f（183-207）肽的特定氨基酸对其对食源性病原体单核细胞增生李斯特菌和坂崎克罗伊氏菌的抗菌活性的重要性。肽的修剪揭示了肽的C-末端的残基对于活性是重要的。去除C-末端的最后5个氨基酸并将肽序列的第23位的Arg替换为Ala残基显著降低了活性。这些发现表明Arg 23对于肽的最佳活性非常重要。在α（s2）-酪蛋白f（183-207）肽的15和17位也带正电荷的Lys残基的取代也引起抗C的有效性的显著降低。sakazakii，其指出了肽的正电荷对于其生物活性的重要性。事实上，同时替换各种带正电荷的氨基酸与杀菌活性的丧失有关。另一方面，在位置14和20处的Pro残基的替换导致显著增加的抗菌效力，并且用多个Trp或Phe残基标记α（s2）-酪蛋白f（193-203）和α（s2）-酪蛋白f（197-207）肽的疏水末端显著增加了它们对L.单核细胞增多症。最后，还测定了pH（4.5至7.4）、温度（4 ℃至37 ℃）和添加钠盐和钙盐（1%至3%）对15-氨基酸α（s2）-酪蛋白f（193-207）肽的活性的影响，并且显示其生物活性在高盐环境中完全消失。
Template-based studies on antimicrobial peptide (AMP) derivatives obtained through manipulation of the amino acid sequence are helpful to identify properties or residues that are important for biological activity. The present study sheds light on the importance of specific amino acids of the milk-derived alpha(s2)-casein f(183-207) peptide to its antibacterial activity against the food-borne pathogens Listeria monocytogenes and Cronobacter sakazakii. Trimming of the peptide revealed that residues at the C-terminal end of the peptide are important for activity. Removal of the last 5 amino acids at the C-terminal end and replacement of the Arg at position 23 of the peptide sequence by an Ala residue significantly decreased activity. These findings suggest that Arg23 is very important for optimal activity of the peptide. Substitution of the also positively charged Lys residues at positions 15 and 17 of the alpha(s2)-casein f(183-207) peptide also caused a significant reduction of the effectiveness against C. sakazakii, which points toward the importance of the positive charge of the peptide for its biological activity. Indeed, simultaneous replacement of various positively charged amino acids was linked to a loss of bactericidal activity. On the other hand, replacement of Pro residues at positions 14 and 20 resulted in a significantly increased antibacterial potency, and hydrophobic end tagging of alpha(s2)-casein f(193-203) and alpha(s2)-casein f(197-207) peptides with multiple Trp or Phe residues significantly increased their potency against L. monocytogenes. Finally, the effect of pH (4.5 to 7.4), temperature (4 degrees C to 37 degrees C), and addition of sodium and calcium salts (1% to 3%) on the activity of the 15-amino-acid alpha(s2)-casein f(193-207) peptide was also determined, and its biological activity was shown to be completely abolished in high-saline environments.