Enzymatic Synthesis of Nucleoside Analogues

Enzymatic synthesis of nucleoside analogues harnesses the regio- and stereoselectivity of biocatalysts to construct modified nucleosides under mild, aqueous conditions. Central to this approach are nucleoside phosphorylases and glycosyltransferases, which catalyse the reversible cleavage and formation of the glycosidic bond with exquisite control over anomeric configuration and attachment site. Advances in enzyme discovery, protein engineering and reaction engineering have broadened substrate scope to include a variety of modified bases and sugars, enabling access to key antiviral, anticancer and vaccine-related compounds. Cascade biocatalysis integrates multiple enzymatic steps in one pot, reducing purification steps and environmental burden while delivering high regioselectivity. Recent progress has extended beyond canonical N-glycosides to encompass C-glycosides and non-natural regioisomers, illustrating both the plasticity and limits of enzyme active sites. These methods underpin more sustainable and scalable routes to therapeutic nucleoside analogues, uniting structural biology insights with applied process development to meet growing demands for novel drug candidates and vaccine constituents.

Research from Nature Portfolio

Recent studies have revealed that wild-type nucleoside phosphorylases can form an unexpected N7-ribosylation product of xanthine, yielding N7-xanthosine rather than the canonical N9 isomer. This discovery challenges the prevailing view of perfect N9-selectivity in purine glycosylation and demonstrates that primary-metabolism enzymes can furnish non-native regioisomers with distinct physicochemical properties, such as altered absorption spectra, equilibrium constants of phosphorolysis and acidity profiles. The identification of N7-xanthosine underscores the potential of natural enzyme promiscuity to generate novel scaffolds for biochemical and therapeutic exploration.

Enzymatic Synthesis of Nucleoside Analogues publication trend

The graph below shows the total number of articles in enzymatic synthesis of nucleoside analogues across all publications each year (not limited to Nature Index journals).

Technical terms

Nucleoside phosphorylase: Enzyme that catalyses reversible phosphorolysis and formation of nucleosides, cleaving or forming the glycosidic bond between base and sugar.

Regioselectivity: Preference of a chemical reaction to occur at one position on a molecule over other possible sites.

Glycosylation: Enzymatic attachment of a sugar moiety to a nucleobase, forming a nucleoside.

Cascade biocatalysis: Sequential enzymatic reactions conducted in a single vessel without intermediate purification, enabling multi-step conversions.

Pseudouridine synthase: Enzyme that catalyses isomerisation of uridine to pseudouridine or installs C-glycosidic linkages in related pathways.

Ribose-1-phosphate: Sugar-phosphate intermediate generated by phosphorylases, serving as a donor for glycosylation reactions.

References

1. Nucleoside Phosphorylases make N7-xanthosine. Nature Communications (2024).
2. Biased Borate Esterification during Nucleoside Phosphorylase‐Catalyzed Reactions: Apparent Equilibrium Shifts and Kinetic Implications**. Angewandte Chemie International Edition (2023).
3. C‑Ribosylating Enzymes in the (Bio)Synthesis of C‑Nucleosides and C‑Glycosylated Natural Products. ACS Catalysis (2023).
4. A deamination-driven biocatalytic cascade for the synthesis of ribose-1-phosphate. Green Chemistry (2024).