Non-canonical amino acids (ncAAs) have emerged as important players in the production of pharmaceuticals, expanding the functional pool of canonical amino acids (cAAs). Biosynthesis of ncAAs has gained prominence due to its eco-friendly nature and efficiency compared to traditional chemical synthesis methods. Genetic code expansion (GCE) techniques have revolutionized the incorporation of ncAAs into target proteins, granting them unique functions and biological activities. This process, which allows the biosynthesis of ncAAs and their integration into proteins within a single microbe, presents exciting opportunities for diverse applications.
Proteins, essential for various life processes, are mostly composed of 20 cAAs. The limitations of these cAAs in facilitating complex biological functions have spurred the need for ncAAs with additional functional groups like ketone, amide, and sulfonate. NcAAs, derivatives of cAAs, offer diverse functional groups enabling protein modification. Over 200 ncAAs can now be incorporated into proteins using GCE technologies, revolutionizing protein research in fields like biology and medicine.
While the synthesis of ncAAs presents challenges such as harsh reaction conditions and high costs, metabolic engineering offers a sustainable solution by leveraging enzyme mechanisms to produce these compounds efficiently. Recent studies have successfully biosynthesized valuable compounds like 5-hydroxytryptophan and L-homoserine using microbial fermentation and metabolic engineering techniques. These advancements highlight the potential of metabolic engineering in green and cost-effective ncAA production.
Methods for ncAA incorporation into proteins include GCE techniques like stop codon suppression (SCS), synonymous codon compression, selective pressure incorporation (SPI), and solid-phase peptide synthesis (SPPS). GCE based on SCS exploits the redundancy of stop codons to encode ncAAs, while synonymous codon compression reallocates codons for ncAA incorporation. SPI and SPPS offer in vivo and in vitro approaches, respectively, for incorporating ncAAs into proteins, enabling precise modifications and enhancing protein functions.
Furthermore, cell-free protein synthesis (CFPS) and other techniques like split inteins and sortases provide additional avenues for ncAA incorporation into proteins. These methods allow for rapid and high-throughput protein production, offering flexibility in protein design and engineering. The integration of advanced technologies like genome-scale models of metabolism and computational biology has augmented the efficiency of ncAA biosynthesis and protein modification, paving the way for the development of novel proteins with diverse functions.
In conclusion, the biosynthesis of ncAAs and their incorporation into proteins represent a cutting-edge frontier in biotechnology, offering exciting possibilities for tailor-made protein engineering. By combining metabolic engineering, GCE techniques, and advanced protein synthesis methods, researchers are unlocking new avenues for protein modification and functional enhancement. The convergence of these technologies holds promise for revolutionizing protein research and biopharmaceutical development in the future.
- Biosynthesis of ncAAs through metabolic engineering offers green and cost-effective production solutions.
- GCE techniques like SCS and synonymous codon compression enable precise ncAA incorporation into proteins.
- In vitro methods like SPPS and CFPS provide versatile platforms for protein synthesis and modification.
- Advanced technologies like split inteins and sortases enhance protein ligation and modification capabilities.
Tags: metabolic flux, attenuated vaccines, computational biology, protein engineering, proteomics, bioinformatics, microbial fermentation, genome editing, metabolic engineering, directed evolution
Read more on pmc.ncbi.nlm.nih.gov