Buforin

This peptide, also referred to as Buforin II peptide is a 21 amino acid peptide derived from Buforin I peptide that is isolated from the Asian toad Bufo gargarizans. The 21 amino acid peptide has been shown to possess anti-microbial activity by penetrating bacteria and inhibiting cellular functions. This antimicrobial peptide interacts with phospholipid bilayers and can be efficiently translocated accross the layer with a weak membrane permeabilization activity. The proline hinge in Buforin 2 is responsible for these cell penetrating properties. This class of antibacterial peptides therefore targets intracellular molecules, most probably nucleic acids, without significantly permeting cell membranes.
In comparison to magainin 2, this peptide binds DNA and RNA from E.coli with a much greater affinity. It is also considered a cell-delivery peptide and has been shown to deliver SiRNAs into cells followed by effective mRNA degradation.