Wiktionary
beta-peptide
n. (context biochemistry English) Any artificial peptide made from beta-amino acids; used in some antibiotics in an attempt to counter resistance.
Wikipedia
Beta-peptide
β-peptides consist of β amino acids, which have their amino group bonded to the β carbon rather than the α carbon as in the 20 standard biological amino acids. The only common naturally occurring β amino acid is β-alanine; although it is used as a component of larger bioactive molecules, β-peptides in general do not appear in nature. For this reason β-peptide-based antibiotics are being explored as ways of evading antibiotic resistance. Early studies in this field were published in 1996 by the group of Dieter Seebach and that of Samuel Gellman.