Expanding the Genetic Code of Bioelectrocatalysis and Biomaterials.

Genetic code expansion is a promising genetic engineering technology that incorporates noncanonical amino acids into proteins alongside the natural set of 20 amino acids. This enables the precise encoding of non-natural chemical groups in proteins. This review focuses on the applications of genetic code expansion in bioelectrocatalysis and biomaterials.

Self-assembly of temperature-responsive di-block polypeptides functionalized with unnatural amino acids.

The incorporation of unnatural amino acids (uAAs) into protein-based polymers has emerged as a powerful methodology to expand their chemical repertoire. Recently, we demonstrated that incorporating uAAs into two temperature-responsive protein-based polymers-namely resilin- and elastin-like polypeptides (RLPs and ELPs, respectively)-can alter their properties. In this study, we incorporated aromatic uAAs into the protein sequence of RLP-ELP diblocks to yield new and diverse assemblies from a single DNA template.

Robust Photocontrol of Elastin-like Polypeptide Phase Transition with a Genetically Encoded Arylazopyrazole.

The rational design of light-responsive proteins and protein-based polymers requires both a photoswitch with suitable light-responsive properties and the ability to incorporate it at (multiple) defined positions in the protein chain. This Letter describes the evolution of high-performance aminoacyl-tRNA synthetases for recognizing a photoswitchable arylazopyrazole-bearing unnatural amino acid (AAP-uAA), which we then incorporated at multiple sites within elastin-like polypeptides (ELPs). The incorporation of AAP-uAA into ELPs yielded proteins capable of an isothermal, reversible, and robust light-mediated soluble-to-insoluble phase transition, which occurred faster (after only 1 min of light irradiation) and demonstrated a larger transition temperature difference (up to a 45 °C difference in the ELP transition temperature upon a cis to trans AAP isomerization) than similar azobenzene-containing ELPs.

Expanding the chemical repertoire of protein-based polymers for drug-delivery applications.

Expanding the chemical repertoire of natural and artificial protein-based polymers (PBPs) can enable the production of sequence-defined, yet chemically diverse, biopolymers with customized or new properties that cannot be accessed in PBPs composed of only natural amino acids. Various approaches can enable the expansion of the chemical repertoire of PBPs, including chemical and enzymatic treatments or the incorporation of unnatural amino acids. These techniques are employed to install a wide variety of chemical groups-such as bio-orthogonally reactive, cross-linkable, post-translation modifications, and environmentally responsive groups-which, in turn, can facilitate the design of customized PBP-based drug-delivery systems with modified, fine-tuned, or entirely new properties and functions.

Tuning the Properties of Protein-Based Polymers Using High-Performance Orthogonal Translation Systems for the Incorporation of Aromatic Non-Canonical Amino Acids.

The incorporation of non-canonical amino acids (ncAAs) using engineered aminoacyl-tRNA synthetases (aaRSs) has emerged as a powerful methodology to expand the chemical repertoire of proteins. However, the low efficiencies of typical aaRS variants limit the incorporation of ncAAs to only one or a few sites within a protein chain, hindering the design of protein-based polymers (PBPs) in which multi-site ncAA incorporation can be used to impart new properties and functions. Here, we determined the substrate specificities of 11 recently developed high-performance aaRS variants and identified those that enable an efficient multi-site incorporation of 15 different aromatic ncAAs.