Class IIa bacteriocin antimicrobial peptides (AMPs) are a compelling alternative to current antimicrobials because of potential specific activity toward antibiotic-resistant bacteria, including vancomycin-resistant enterococci. Engineering of these molecules would be enhanced by a better understanding of AMP sequence-activity relationships to improve efficacy in vivo and limit effects of off-target activity. Toward this goal, we experimentally evaluated 210 natural and variant class IIa bacteriocins for antimicrobial activity against six strains of enterococci. Inhibitory activity was ridge regressed to AMP sequence to predict performance, achieving an area under the curve of 0.70 and demonstrating the potential of statistical models for identifying and designing AMPs. Active AMPs were individually produced and evaluated against eight enterococcus strains and four Listeria strains to elucidate trends in susceptibility. It was determined that the mannose phosphotransferase system (manPTS) sequence is informative of susceptibility to class IIa bacteriocins, yet other factors, such as membrane composition, also contribute strongly to susceptibility. A broadly potent bacteriocin variant (lactocin DT1) from a Lactobacillus ruminis genome was identified as the only variant with inhibitory activity toward all tested strains, while a novel enterocin variant (DT2) from an Enterococcus faecium genome demonstrated specificity toward Listeria strains. Eight AMPs were evaluated for proteolytic stability to trypsin, chymotrypsin, and pepsin, and three C-terminal disulfide-containing variants, including divercin V41, were identified as compelling for future in vivo studies, given their high potency and proteolytic stability.

中文翻译：

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天然和IIa类细菌素的挖掘和统计模型阐明了物种间的活性和选择性。

IIa类细菌素抗菌肽（AMPs）是目前抗微生物剂的引人注目的替代品，因为它对包括耐万古霉素的肠球菌在内的抗生素耐药细菌具有潜在的比活性。通过更好地了解AMP序列与活性之间的关系以提高体内功效，可以增强这些分子的工程设计并限制脱靶活动的影响。为了实现这一目标，我们通过实验评估了210种天​​然和变体IIa类细菌素对六种肠球菌的抗菌活性。抑制活性被降低到AMP序列，以预测性能，达到0.70的曲线下面积，并证明了用于识别和设计AMP的统计模型的潜力。单独生产活性AMP，并针对八种肠球菌菌株和四种李斯特菌进行评估菌株以阐明易感性趋势。已确定甘露糖磷酸转移酶系统（manPTS）序列对IIa类细菌素易感性提供了信息，而其他因素（例如膜组成）也对易感性有很大贡献。来自乳杆菌基因组的广谱细菌素变体（lactocin DT1）被鉴定为对所有测试菌株均具有抑制活性的唯一变体，而来自粪肠球菌基因组的新型肠球菌变体（DT2）表现出对利斯特氏菌的特异性株。八安培的蛋白水解稳定性，以胰蛋白酶，糜蛋白酶，胃蛋白酶和进行评价，和三个C-末端含二硫化物的变体，包括divercin V41，被确定为引人注目以供将来在体内研究中，由于其高效力和蛋白水解稳定性。