A biocatalytic platform for asymmetric alkylation of alpha-keto acids by mining and engineering of methyltransferases

Type
Journal Article
Author
Shuyun Ju
Kaylee Kuzelka
Rui Guo
Benjamin Krohn-Hansen
Jianping Wu
Satish Nair
Yang Yang
Year of Publication
2023
Number
1
Volume
14
URL
https://doi.org/10.1038/s41467-023-40980-w
DOI
10.1038/s41467-023-40980-w
User Type
In-House
Facility
Characterization (UCSB)
Abstract

Catalytic asymmetric $\alpha$-alkylation of carbonyl compounds represents a long-standing challenge in synthetic organic chemistry. Herein, we advance a dual biocatalytic platform for the efficient asymmetric alkylation of $\alpha$-keto acids. First, guided by our recently obtained crystal structures, we develop SgvMVAV as a general biocatalyst for the enantioselective methylation, ethylation, allylation and propargylation of a range of $\alpha$-keto acids with total turnover numbers (TTNs) up to 4,600. Second, we mine a family of bacterial HMTs from Pseudomonas species sharing less than 50\% sequence identities with known HMTs and evaluated their activities in SAM regeneration. Our best performing HMT from P. aeruginosa, PaHMT, displays the highest SAM regeneration efficiencies (TTN up to 7,700) among HMTs characterized to date. Together, the synergistic use of SgvMVAV and PaHMT affords a fully biocatalytic protocol for asymmetric methylation featuring a record turnover efficiency, providing a solution to the notorious problem of asymmetric alkylation.