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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. ==Chemical structure and synthesis== In α amino acids (molecule at left), both the carboxylic acid group (red) and the amino group (blue) are bonded to the same carbon center, termed the α carbon () because it is one atom away from the carboxylate group. In β amino acids, the amino group is bonded to the β carbon (), which is found in most of the 20 standard amino acids. Only glycine lacks a β carbon, which means that β-glycine is not possible. The chemical synthesis of β amino acids can be challenging, especially given the diversity of functional groups bonded to the β carbon and the necessity of maintaining chirality. In the alanine molecule shown, the β carbon is achiral; however, most larger amino acids have a chiral atom. A number of synthesis mechanisms have been introduced to efficiently form β amino acids and their derivatives notably those based on the Arndt-Eistert synthesis. Two main types of β-peptides exist: those with the organic residue (R) next to the amine are called β3-peptides and those with position next to the carbonyl group are called β2-peptides. : 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Beta-peptide」の詳細全文を読む スポンサード リンク
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