Most biological protein synthesis is mediated by the ribosome, and employs ∼20 proteinogenic amino acids as building blocks. Through the use of misacylated tRNAs, presently accessible by any of several strategies, it is now possible to employ in vitro and in vivo protein biosynthesis to elaborate proteins containing a much larger variety of amino acid building blocks. However, the incorporation of this broader variety of amino acids is limited to those species utilized by the ribosome. As a consequence, virtually all of the substrates utilized over time have been L-α-amino acids. In recent years, a variety of structural and biochemical studies have provided important insights into those regions of the 23S ribosomal RNA that are involved in peptide bond formation. Subsequent experiments, involving the randomization of key regions of 23S rRNA required for peptide bond formation, have afforded libraries of E. coli harboring plasmids with the rrnB gene modified in the key regions. Selections based on the use of modified puromycin derivatives with altered amino acids then identified clones uniquely sensitive to individual puromycin derivatives. These clones often recognized misacylated tRNAs containing altered amino acids similar to those in the modified puromycins, and incorporated the amino acid analogues into proteins. In this fashion, it has been possible to realize the synthesis of proteins containing D-amino acids, β-amino acids, phosphorylated amino acids, as well as long chain and cyclic amino acids in which the nucleophilic amino group is not in the α-position. Of special interest have been dipeptides and dipeptidomimetics of diverse utility.

大多数生物蛋白质合成由核糖体介导，并使用约 20 种蛋白质氨基酸作为构建块。通过使用目前可通过多种策略中的任何一种获得的错酰化 tRNA，现在可以在体外和体内使用蛋白质生物合成，以精制含有更多种类氨基酸结构单元的蛋白质。然而，这种更广泛种类的氨基酸的掺入仅限于核糖体利用的那些种类。因此，随着时间的推移，几乎所有使用的底物都是 L-α-氨基酸。近年来，各种结构和生化研究对 23S 核糖体 RNA 中参与肽键形成的那些区域提供了重要的见解。随后的实验，涉及肽键形成所需的 23S rRNA 关键区域的随机化，提供了大肠杆菌文库携带在关键区域修饰了 rrnB 基因的质粒。基于使用具有改变的氨基酸的修饰的嘌呤霉素衍生物的选择随后鉴定出对单个嘌呤霉素衍生物独特敏感的克隆。这些克隆通常识别含有与修饰的嘌呤霉素相似的改变氨基酸的错误酰化 tRNA，并将氨基酸类似物掺入蛋白质中。以这种方式，已经可以实现含有D-氨基酸、β-氨基酸、磷酸化氨基酸以及亲核氨基不在α-的长链和环状氨基酸的蛋白质的合成。位置。特别感兴趣的是具有多种用途的二肽和二肽模拟物。