Genetic code expansion (GCE) is a cutting-edge synthetic biology technology that enables the site-specific incorporation of non-canonical amino acids (ncAAs) into proteins. By embedding chemically reactive ncAAs, researchers gain precise control over protein functionality and bioconjugation, driving innovation in drug discovery, chemical biology, and material science. As your pioneering biotechnology partner, we provide comprehensive, end-to-end solutions for chemical reactive ncAA incorporation. Our proprietary and dedicated GCEngine platform delivers seamless services, from orthogonal pair identification and in vitro validation to in vivo application development, empowering you to engineer proteins with novel, bio-orthogonal handles for superior functionality.
Chemical reactive ncAAs are synthetic building blocks equipped with unique functional groups, such as azides, alkynes, alkenes, or aryl halides. These side chains are designed to participate in highly specific, bio-orthogonal reactions, enabling precise protein modification under physiological conditions without perturbing native biological processes. By bypassing the limitations of traditional cysteine or lysine labeling, these reactive handles ensure that subsequent conjugations occur with regioselectivity and stoichiometry.
Fig.1 Chemical crosslinkers. (Aydin, Y., and Coin, I., 2023)
The incorporation process involves the repurposing of a specific codon, typically the amber stop codon, to encode an ncAA bearing the desired reactive handle. This is achieved using an engineered orthogonal aminoacyl-tRNA synthetase (aaRS) and its cognate tRNA (tRNA), a pair that functions independently of the host's endogenous translation machinery. Once integrated, these functional groups serve as "bio-orthogonal anchors" for the precise attachment of external payloads.
Precision & Specificity
Enables attachment of payloads (e.g., fluorophores, toxins, PEG) to a single, defined site on a protein. This ensures homogeneous conjugate formation and consistent structure-activity relationships, in stark contrast to the heterogeneous mixtures generated by traditional lysine or cysteine-based chemistry.
Bio-orthogonal Compatibility
Leverages high-fidelity, rapid reactions like strain-promoted azide-alkyne cycloaddition (SPAAC) or inverse electron-demand Diels-Alder (IEDDA). These reactions proceed efficiently in complex biological milieus with minimal background noise, facilitating applications in live cells or crude lysates.
Minimal Structural Disruption
When strategically placed, the ncAA can be introduced with minimal perturbation to the protein's native folding, stability, and biological activity, enabling precise "tag-and-modify" strategies.
Versatile Downstream Modification
Provides a universal platform for modifying a wide range of proteins, including antibodies, enzymes, and peptides, for diverse downstream applications in therapeutics, diagnostics, and materials science.
| Application Area | Description |
| Therapeutic Bioconjugation | Site-specific creation of antibody-drug conjugates (ADCs), peptide-drug conjugates, or PEGylated therapeutics. Enhances pharmacokinetics, target specificity, and therapeutic index while reducing off-target toxicity. |
| Biomolecular Imaging & Probes | Incorporation of ncAAs with clickable handles for attaching fluorescent dyes, MRI contrast agents, or other probes. Enables super-resolution imaging, pulse-chase studies, and real-time tracking of protein dynamics in living systems. |
| Protein Immobilization & Materials Science | Facilitates oriented, covalent attachment of enzymes to solid supports for improved biocatalysis, or precise incorporation of proteins into hydrogels and biomaterials with controlled spatial organization. |
| Protein-Protein Interaction Mapping | Incorporation of photo-crosslinking ncAAs (e.g., benzophenone analogs) to capture and identify transient, weak, or spatially restricted protein interactions in living cells. |
| Stability & Pharmacokinetic Optimization | Introduction of ncAAs that facilitate site-specific conjugation to serum albumin or other carriers, potentially enhancing in vivo stability and half-life of peptide and protein therapeutics. |
Built on a foundation of high-throughput screening and directed evolution, our proprietary GCEngine platform offers an integrated solution for chemical-reactive ncAA incorporation. Our services encompass screening and optimizing orthogonal aaRS/tRNA pairs for your ncAA of interest, validating incorporation efficiency and fidelity in both cell-free (CFPS) and cellular expression systems, and scaling up production of the modified protein. We also provide downstream bioconjugation support, utilizing established bio-orthogonal protocols to link your precisely engineered protein to desired payloads.
Our platform is compatible with a broad and expanding repertoire of chemically reactive ncAAs, each offering a distinct bio-orthogonal handle for downstream conjugation.
Ketone/Aldehyde-bearing ncAAs
Representative ncAAs: p-Acetylphenylalanine (pAcF), Formyllysine.
Description: The ketone or aldehyde carbonyl groups react specifically with hydrazines or alkoxyamines to form stable hydrazones or oximes, respectively. This chemoselective ligation is frequently employed for fluorescent labeling, biotinylation, or PEGylation of recombinant proteins under physiological conditions, offering a robust alternative to amine-directed chemistry.
Azide/Alkyne-bearing ncAAs
Representative ncAAs: Azidohomoalanine (Aha), p-Azidophenylalanine.
Description: These ncAAs provide quintessential handles for copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) or strain-promoted azide-alkyne cycloaddition (SPAAC). The resulting triazole linkage is highly stable and forms efficiently in complex biological milieus, making this approach indispensable for live-cell imaging, activity-based protein profiling, and the construction of ADCs.
Alkyl Halide-bearing ncAAs
Representative ncAAs: p-Bromomethyl-L-phenylalanine (pBmp).
Description: These ncAAs feature activated benzylic or α-halo carbonyl electrophiles that readily undergo nucleophilic substitution with thiols. This reactivity enables selective cysteine alkylation, disulfide bond rebridging in antibodies, and stable bioconjugate formation under mild conditions. Additionally, aryl halide variants (e.g., p-iodophenylalanine) serve as heavy-atom derivatives for X-ray crystallography.
Strained Alkene/Alkyne-bearing ncAAs
Representative ncAAs: trans-Cyclooctene-L-lysine (TCO-Lys), Bicyclononyne-lysine (BCN-Lys).
Description: Engineered with ring strain to dramatically accelerate reaction kinetics, these ncAAs participate in catalyst-free bioorthogonal reactions. TCO derivatives react extremely rapidly with tetrazines via IEDDA chemistry, while BCN derivatives are common SPAAC reagents. Their fast reaction rates are critical for real-time tracking of dynamic processes in vivo.
Sulfur(VI) Fluoride-bearing ncAAs (for SuFEx Chemistry)
Representative ncAAs: Fluorosulfate-tyrosine (FSY), Fluorosulfonyloxybenzoyl-lysine (FSK).
Description: Represent the next-generation "SuFEx" click chemistry platform. The S(VI)-F moiety reacts selectively with various nucleophiles (e.g., phenols, amines) under physiological conditions, enabling the formation of stable sulfate or sulfonate linkages. This emergent class is particularly valued for developing covalent inhibitors and constructing stable protein conjugates and biomaterials.
By leveraging our expertise in GCE and deep understanding of bioorthogonal chemistry, we provide our partners with reliable, precise, and innovative tools to overcome the limitations of conventional protein modification. Our end-to-end service model, from concept to conjugate, is designed to accelerate your research in therapeutic development, diagnostic tool creation, and fundamental biological discovery. We invite you to contact us to discuss how our chemical reactive ncAA incorporation services can empower your project.
All our services are exclusively intended for preclinical research purposes. They are not intended for diagnostic, therapeutic, or patient management applications.
A specialized platform advancing genetic code expansion through orthogonal tRNA/aaRS technologies, enabling precise ncAA incorporation for biotherapeutic development, synthetic biology, and diagnostics.