Intrinsically Disordered Ku Protein-Derived Cell-Penetrating Peptides

Efficient delivery of bioactive ingredients into cells is a major challenge. Cell-penetrating peptides (CPPs) have emerged as promising vehicles for this purpose. We have developed novel CPPs derived from the flexible and disordered tail extensions of DNA-binding Ku proteins. Ku-P4, the lead CPP identified in this study, is biocompatible and displays high internalization efficacy. Biophysical studies show that the proline residue is crucial for preserving the intrinsically disordered state and biocompatibility. DNA binding studies showed effective DNA condensation to form a positively charged polyplex. The polyplex exhibited effective penetration through the cell membrane and delivered the plasmid DNA inside the cell. These novel CPPs have the potential to enhance the cellular uptake and therapeutic efficacy of peptide-drug or gene conjugates.

Automated summary

Efficient delivery of bioactive ingredients into cells remains a challenge, and cell-penetrating peptides (CPPs) have emerged as promising delivery vehicles. In this study, novel CPPs derived from the flexible and disordered tail extensions of DNA-binding Ku proteins were developed. The lead CPP, Ku-P4, demonstrated high internalization efficacy and biocompatibility. The presence of proline residue was crucial for maintaining the intrinsically disordered state and biocompatibility. Biophysical and DNA binding studies revealed that Ku-P4 efficiently condensed DNA into positively charged polyplexes, which were then able to penetrate the cell membrane and deliver the plasmid DNA inside the cell. These findings suggest that these novel CPPs have the potential to enhance the cellular uptake and therapeutic efficacy of peptide-drug or gene conjugates.