Application of l-Threonine Aldolase to on-DNA Reactions

A Robust Strategy for Introducing Amino-Modifiers in Nucleic Acids: Enabling Novel Amino Tandem Oligonucleotide Synthesis in DNA and RNA

Amino-modifiers are pivotal chemical modifications in nucleic acid scaffolds, serving applications ranging from (bio)conjugation to probing the origins of life. We report a simple, efficient, and cost-effective methodology for the introduction of amino-modifiers into DNA and RNA. This approach leverages a commercially available sulfonyl-containing solid support, which is first converted into a mixed N-hydroxysuccinimide carbonate, enabling robust conjugation with primary and secondary amines whether nucleosidic or non-nucleosidic. Oligonucleotides are synthesized via solid-phase synthesis and purified using standard methods, with little to no modification. Building on this framework, we introduce a novel amino-containing tandem oligonucleotide synthesis (aTOS) methodology, which facilitates the introduction of multiple terminal amino (or monophosphate) groups across two oligonucleotide strands. This innovative method broadens the toolkit for the introduction of amino modifications in nucleic acids, for applications in nucleic acid (bio)chemistry and biotechnology.

Synthesis of 3-Phenylserine by a Two-enzyme Cascade System with PLP Cofactor

A two-enzyme cascade system containing ω-transaminase (ω-TA) and L-threonine aldolase (L-ThA) was reported for the synthesis of 3-Phenylserine starting from benzylamine, and PLP was utilized as the only cofactor in these both two enzymes reaction system. Based on the transamination results, benzylamine was optimized as an advantageous amino donor as confirmed by MD simulation results. This cascade reaction system could not only facilitate the in situ removal of the co-product benzaldehyde, enhancing the economic viability of the reaction, but also establish a novel pathway for synthesizing high-value phenyl-serine derivatives. In our study, nearly 95 % of benzylamine was converted, yielding over 54 % of 3-Phenylserine under the optimized conditions cascade reaction.

Substrate access path-guided engineering of L-threonine aldolase for improving diastereoselectivity

The L-threonine aldolase from Leishmania major was engineered to improve diastereoselectivity by a CAST/ISM strategy, providing insights into the relationship between physico -chemical properties of substrate access path and diastereoselectivity....