Click PR9 – Click Peptides

Cell penetrating peptides (CPP) can transport molecules such as nucleic acids, proteins, and imaging agents into cells of interest. Pas PR9, nona-arginine, is an arginine rich CPP. It is composed of the nona-arginine: R9 and Pas which is a peptide penetrating accelerating sequence (PAS) and it functions to export molecules out of endocytic vesicles. During a study in which PR9 was in complex with a Quantum dot probe (QD) it was evident that the PR9/QD complex was transported into the cell through endocytosis and co-localises with actins, lysosomes, early endosomes and the nucleus. Due to the non-toxicity of the PR9/QD complex it can be used as a safe vector for biomedical purposes. PR9 is provided here with a N-terminal alkyne attachment. Two of the most regularly encountered functional groups for click chemistry are azides and alkynes, and the azide-alkyne cycloaddition has become the most popular click reaction. The use of click chemistry with alkyne- PR9 allows a wide variety of applications particularly for conjugation, modification, and peptide design.