CAS Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China; School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.
CAS Key Laboratory of Nano-Bio Interface, Division of Nanobiomedicine, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou, China; School of Nano-Tech and Nano-Bionics, University of Science and Technology of China, Hefei, China.
J Biol Chem. 2021 Dec;297(6):101364. doi: 10.1016/j.jbc.2021.101364. Epub 2021 Nov 2.
Peptide conformation can change subject to environment cues. This concept also applies to many cationic amphipathic peptides (CAPs) known to have cell membrane lytic or penetrative activities. Well-conditioned CAPs can match the properties of the target membrane to support their intended biological functions, e.g., intracellular cargo delivery; however, the intricacy in such conditioning surpasses our current understanding. Here we focused on hydrophobicity, a key biophysical property that dictates the membrane activity of CAPs, and applied a structure-function strategy to evolve a template peptide for endosomolytic cargo delivery. The template was subjected to iterative adjustment to balance hydrophobicity between its N-terminal linear and C-terminal helical domains. We demonstrate that the obtained peptide, LP6, could dramatically promote cargo cell entry and facilitate cytosolic delivery of biomacromolecules such as FITC-dextran, saporin, and human IgG. Among the evolved peptide series, LP6 has low cytotoxicity and moderate hydrophobicity, exhibits maximum change in helical conformation in response to negatively charged phospholipids, and also shows an apparent aggregational behavior in response to sialic acid enrichment. These attributes of LP6 collectively indicate that its anion-responsive conformational change is a critical underlining of its endosomolytic cargo delivery capability. Our results also suggest that modulation of hydrophobicity serves as a key to the precise tuning of CAP's membrane activity for future biomedical applications.
肽构象可以根据环境线索发生变化。这一概念也适用于许多具有细胞膜裂解或穿透活性的阳离子两亲肽（CAP）。经过良好条件处理的 CAP 可以与目标膜的特性相匹配，以支持其预期的生物学功能，例如细胞内货物的传递；然而，这种调节的复杂性超出了我们目前的理解。在这里，我们专注于疏水性，这是决定 CAP 膜活性的关键物理性质，并应用结构-功能策略来设计用于内体溶胞货物传递的模板肽。该模板经过反复调整，以平衡其 N 端线性和 C 端螺旋域之间的疏水性。我们证明，所得的肽 LP6 可以显著促进货物进入细胞，并促进生物大分子如 FITC-葡聚糖、丝裂霉素和人 IgG 的细胞质内递送。在进化的肽系列中，LP6 具有低细胞毒性和中等疏水性，对带负电荷的磷脂表现出最大的螺旋构象变化，并且对唾液酸富集也表现出明显的聚集行为。LP6 的这些特性表明，其阴离子响应的构象变化是其内体溶胞货物传递能力的关键基础。我们的结果还表明，疏水性的调节是未来生物医学应用中精确调整 CAP 膜活性的关键。
