Pinpointing critical positions: Alanine and lysine scans demonstrate that substituting amino acids 5 and 9 increases the activity of KR‐12 against human pathogens. Cationic substitutions in other positions lead to changes in specificity. Membrane‐permeabilisation assays show the same trends, which indicate membrane disruption as a mechanism of action, but peptides show no cytotoxic activity against human cells.

中文翻译：

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LL 37衍生肽片段KR-12的丙氨酸和赖氨酸扫描揭示了抗菌活性的关键残基

查明关键位置：丙氨酸和赖氨酸扫描表明，用氨基酸5和9取代可增加KR-12抵抗人类病原体的活性。其他位置的阳离子取代会导致特异性变化。膜通透性测定显示出相同的趋势，表明膜破坏是一种作用机制，但是肽对人细胞没有细胞毒性。