Advances in Biosynthesis of Non-Canonical Amino Acids (ncAAs) and the Methods of ncAAs Incorporation into Proteins

Abstract

The functional pool of canonical amino acids (cAAs) has been enriched through the emergence of non-canonical amino acids (ncAAs). NcAAs play a crucial role in the production of various pharmaceuticals. The biosynthesis of ncAAs has emerged as an alternative to traditional chemical synthesis due to its environmental friendliness and high efficiency. The breakthrough genetic code expansion (GCE) technique developed in recent years has allowed the incorporation of ncAAs into target proteins, giving them special functions and biological activities. The biosynthesis of ncAAs and their incorporation into target proteins within a single microbe has become an enticing application of such molecules. Based on that, in this study, we first review the biosynthesis methods for ncAAs and analyze the difficulties related to biosynthesis. We then summarize the GCE methods and analyze their advantages and disadvantages. Further, we review the application progress of ncAAs and anticipate the challenges and future development directions of ncAAs.

Unnatural Amino Acids for Biological Spectroscopy and Microscopy

“…Currently, the amber codon (UAG) is the most frequently used new genetic code, because it is the least used termination codon in E. coli cells (ca. 7%). , Below we only briefly discuss its working principle and direct interested readers to several recent reviews. − …”

Engineered Proteins and Materials Utilizing Residue-Specific Noncanonical Amino Acid Incorporation

“…The correctly aminoacylated tRNAcAA (blue with green sphere) and the misacylated tRNA (red with orange star) are processed by the ribosome to give a globally modified protein. conducive for precise control of protein modification, 11 and depending on the ncAA, it has been shown to have lower incorporation efficiencies than SSI. 19 3.2.1.…”

“…Obtaining enantiomerically pure ncAAs in the quantities required for large-scale applications continues to pose a challenge, though the emerging biocatalytic production methods are proving to be suitable alternatives in terms of cost and sustainability. 11,35,80,81 Biocatalytic synthesis also offers the opportunity of coupling the production of the ncAAs with their incorporation into proteins. 80−83 Schipp et al have demonstrated this by reconfiguring the methionine biosynthetic pathway in an E. coli strain to create a trans-sulfuration pathway for the in-cell production and incorporation of L-azidohomoalanine (Aha).…”

“…10 With the advent of noncanonical amino acids (ncAAs), the permutations of protein sequences, and subsequently their functions, have diversified enormously. 11,12 There have been several comprehensive reviews over the years on different aspects of the incorporation of ncAAs into proteins. 13−20 In this review, we explore the methods and applications of ncAA-bearing proteins and peptide materials, specifically those with ncAAs incorporated through residuespecific means.…”

“…This has allowed for the development of specific protein functions and further tunability by simple reordering of a sequence from a 20 amino acid library . With the advent of noncanonical amino acids (ncAAs), the permutations of protein sequences, and subsequently their functions, have diversified enormously. , …”