Novel approaches are needed to combat antibiotic resistance. Here, we describe a computational–experimental framework for the discovery of novel cryptic antimicrobial peptides (AMPs). The computational platform, based on previously validated antimicrobial scoring functions, indicated the activation peptide of pepsin A, the main human stomach protease, and its N- and C-terminal halves as antimicrobial peptides. The three peptides from pepsinogen A3 isoform were prepared in a recombinant form using a fusion carrier specifically developed to express toxic peptides in Escherichia coli. Recombinant pepsinogen A3-derived peptides proved to be wide-spectrum antimicrobial agents with MIC values in the range 1.56–50 μM (1.56–12.5 μM for the whole activation peptide). Moreover, the activation peptide was bactericidal at pH 3.5 for relevant foodborne pathogens, suggesting that this new class of previously unexplored AMPs may contribute to microbial surveillance within the human stomach. The peptides showed no toxicity toward human cells and exhibited anti-infective activity in vivo, reducing by up to 4 orders of magnitude the bacterial load in a mouse skin infection model. These peptides thus represent a promising new class of antibiotics. We envision that computationally guided data mining approaches such as the one described here will lead to the discovery of antibiotics from previously unexplored sources.

中文翻译：

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通过计算-实验平台从人胃中鉴定新型隐秘多功能抗菌肽

需要新的方法来对抗抗生素抗性。在这里，我们描述了一种用于发现新型隐秘抗菌肽（AMPs）的计算实验框架。该计算平台基于先前验证的抗微生物评分功能，表明胃蛋白酶A的激活肽（人体主要的胃蛋白酶）及其N和C端半部为抗微生物肽。使用专门开发用于在大肠杆菌中表达毒性肽的融合载体以重组形式制备来自胃蛋白酶原A3亚型的三种肽。重组胃蛋白酶原A3衍生肽已被证明是广谱抗菌剂，MIC值在1.56–50μM（整个激活肽为1.56–12.5μM）范围内。此外，活化肽在相关的食源性病原体的pH值为3.5时具有杀菌作用，这表明这种先前未开发的新型AMPs可能有助于人胃中的微生物监测。该肽对人体细胞无毒性，并在体内具有抗感染活性，可将小鼠皮肤感染模型中的细菌负荷降低多达4个数量级。因此，这些肽代表了有前途的新型抗生素。我们设想，以计算为指导的数据挖掘方法（例如此处所述的方法）将导致从以前未开发的来源中发现抗生素。