Department of Biochemistry and Molecular Biology, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA, 70112, USA.
Nat Commun. 2018 Jul 2;9(1):2568. doi: 10.1038/s41467-018-04874-6.
Peptides and analogs such as peptide nucleic acids (PNA) are promising tools and therapeutics, but the cell membrane remains a barrier to intracellular targets. Conjugation to classical cell penetrating peptides (CPPs) such as pTat (tat) and pAntp (penetratin) facilitates delivery; however, efficiencies are low. Lack of explicit design principles hinders rational improvement. Here, we use synthetic molecular evolution (SME) to identify gain-of-function CPPs with dramatically improved ability to deliver cargoes to cells at low concentration. A CPP library containing 8192 tat/penetratin hybrid peptides coupled to an 18-residue PNA is screened using the HeLa pTRE-LucIVS2 splice correction reporter system. The daughter CPPs identified are one to two orders of magnitude more efficient than the parent sequences at delivery of PNA, and also deliver a dye cargo and an anionic peptide cargo. The significant increase in performance following a single iteration of SME demonstrates the power of this approach to peptide sequence optimization.
肽和类似物，如肽核酸 (PNA)，是很有前途的工具和治疗方法，但细胞膜仍然是细胞内靶标的障碍。与经典的细胞穿透肽 (CPP) 如 pTat (tat) 和 pAntp (penetratin) 缀合可促进递送;然而，效率很低。缺乏明确的设计原则阻碍了合理的改进。在这里，我们使用合成分子进化 (SME) 来鉴定具有显著提高功能的 CPP，这些 CPP 能够以低浓度将货物递送到细胞中。使用 HeLa pTRE-LucIVS2 剪接校正报告系统筛选含有 8192 个 tat/penetratin 杂合肽的 CPP 文库。鉴定出的子 CPP 在递送 PNA 方面比母体序列有效 1 到 2 个数量级，并且还递送染料货物和阴离子肽货物。SME 单次迭代后性能的显著提高证明了这种肽序列优化方法的强大功能。
