Delivery of cell membrane impermeable peptides into living cells by using head-to-tail cyclized mitochondria-penetrating peptides.

A series of cyclic Arg-rich mitochondria-penetrating peptides were prepared with variation in the macrocycle size and the chirality of Arg residues. A cyclic heptapeptide was demonstrated to be an efficient mitochondria-specific delivery vector for delivering membrane impermeable peptides.