In a new study led by Prof. Andrew Buller (University of Wisconsin–Madison, USA) in collaboration with Dr. Marc Garcia-Borràs’s group at the IQCC, researchers have tackled the mechanistic limitations of aldolase biocatalysis. Through detailed mechanistic analysis, the team was able to overcome these limitations, enabling efficient C–C bond formation in the synthesis of new amino acids.
Enzymes are renowned for their catalytic efficiency and selectivity, yet many classic transformations in organic synthesis still lack a biocatalytic equivalent. Aldolases, which are powerful enzymes for C–C bond formation, typically react only with activated carbonyl electrophiles, and their broader reactivity has been challenging to expand. In this study, the researchers used a pair of aldolases dependent on pyridoxal phosphate (PLP) to uncover the mechanistic origins of this limitation. They discovered that aldolases are restricted by a kinetically favorable proton transfer with solvent, which disrupts aldol addition into ketones. By using a transaldolase, the team successfully circumvented this barrier, achieving efficient addition into unactivated ketones. The resulting products are highly valuable, non-canonical amino acids featuring chiral tertiary alcohols within their side chains.
Mechanistic analysis reveals that transaldolase activity is an inherent feature of PLP chemistry, providing key insights for expanding aldolase catalysis beyond previously known limitations. This work establishes principles for enabling convergent, enantioselective C–C bond formation from simple starting materials.
This work has been carried out in collaboration between the group of Prof. Andrew Buller (University of Wisconsin–Madison, USA) and the group of Dr. Marc Garcia-Borràs from the IQCC. Dr. Jordi Soler, a former PhD student from Marc’s group, was the leading computational author of the study.
This project is a core part of the research program that Dr. Garcia-Borràs leads at the IQCC, which is devoted to the use of computational methods in combination with experiments to characterize and design new abiological enzymatic activities and synthetically useful biocatalysts: “Biocatalytic intermediates for the discovery and design of new enzymatic activities“.
This work has been recently published open access in Nature Chemistry:
S. K. Bruffy, A. Meza, J. Soler, T. J. Doyon, S. H. Young, J. Lim, K. G. Huseth, P. H. Willoughby, M. Garcia-Borràs* and A. R. Buller*
“Biocatalytic asymmetric aldol addition into unactivated ketones”
Nat. Chem. 2024, ASAP.
DOI: 10.1038/s41557-024-01647-1
Preprint (Open Access): http://doi.org/10.26434/chemrxiv-2023-2v3cq
Girona, November 6th, 2024
For more info: ges.iqcc@udg.edu