By synthesizing a short peptide similar to a family of naturally occurring defense proteins, researchers have created molecules that could lead to an entirely new class of antibiotics (Nature 404, 565, 2000). The sequence of the new β-peptide, which by virtue of its a β-amino acid backbone is resistant to proteolysis in the bloodstream, is based on that of the magainins, short naturally occurring peptides that attack bacterial membranes. In initial tests, the new compound showed impressive antibacterial activity, even against antibiotic-resistant strains. Samuel Gellman, a senior author on the new work, adds that the applications could be even broader: “I am hoping that β-peptides… will prove useful for targeted disruption of specific protein–protein interactions,” and for new treatments for viral diseases and cancer. The team is now working on improving the anitbacterial activity of the new β-peptide in vitro before beginning animal testing.