Crotamine: a novel cell-penetrating polypeptide nanocarrier with potential anti-cancer and biotechnological applications.

Crotamine is a basic, 42-residue polypeptide derived from snake venom that has been shown to possess cell-penetrating properties. Crotamine forms nanoparticles with a variety of DNA and RNA molecules, and crotamine-plasmid DNA nanoparticles are selectively delivered into actively proliferating cells in culture or in mice. As such, these nanoparticles could form the basis for a nucleic acid drug-delivery system. Here we describe the preparation, purification, and biochemical and biophysical analysis of venom-derived, recombinant, chemically synthesized, and fluorescent-labeled crotamine; the formation and characterization of crotamine-DNA and -RNA nanoparticles; and the delivery of these nanoparticles into cells and animals.