Alex Kim (@atkimistry.bsky.social)

I'm very excited to share the newest publication from team PLP. I've been working with this PLP library since my summer rotation in 2021 and it's so exciting to see the first paper finally out! #PLProud @narayanlab.bsky.social pubs.acs.org/doi/10.1021/...

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Profiling of Diverse Pyridoxal-5′-Phosphate Dependent Enzymes Reveals Promiscuous Aldolase Activity with (2-Azaaryl)methanamines The elaboration of amine substrates through C–C bond-forming reactions is important in the synthesis of bioactive small molecules. Pyridoxal-5′-phosphate (PLP)-dependent enzymes have emerged as valuable biocatalysts for this class of reactions, due to their high stereoselectivity and ability to forge new C–C bonds on unprotected α-amino acid substrates. However, the use of abiological primary amines as pronucleophiles with enzymes such as threonine aldolase has been unexplored, moderating the utility of a biocatalytic approach in the synthesis of diverse 1,2-amino alcohols. In this report, we disclose the discovery and engineering of a PLP-dependent aldolase that accepts (2-azaaryl)methanamines in an aldol-type transformation. The 1,2-amino alcohol products generated, which contain representative heteroaromatic pharmacophores, are delivered with control over both the diastereoselectivity and enantioselectivity in the C–C bond-forming event. Protein engineering provided variants with improved binding affinity for the abiological substrate and decreased affinity for the native α-amino acid, overcoming inhibition of the abiotic reaction by components of lysate, a major challenge in reaction discovery with PLP-dependent enzymes such as threonine aldolases. This work represents the first known example of C–C bond formation on nonamino acid substrates with threonine aldolase and provides a platform for further development of complexity-building biocatalytic reactions with abiotic amine substrates. https://pubs.acs.org/doi/10.1021/jacs.5c04098